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SJC-12510

                 COMMONWEALTH   vs.   JOSE L. ARIAS.



        Essex.       September 7, 2018. - March 15, 2019.

       Present:    Gants, C.J., Lenk, Gaziano, & Lowy, JJ.


Constitutional Law, Search and seizure, Probable cause. Search
     and Seizure, Probable cause, Exigent circumstances,
     Emergency, Multiple occupancy building, Protective sweep,
     Plain view. Probable Cause. Practice, Criminal, Motion to
     suppress, Interlocutory appeal, Appeal by Commonwealth.
     Evidence, Informer. Witness, Police informer. Controlled
     Substances.



     Indictments found and returned in the Superior Court
Department on April 14, 2014.

     A pretrial motion to suppress evidence was heard by Mary-
Lou Rup, J.

     An application for leave to prosecute an interlocutory
appeal was allowed by Hines, J., in the Supreme Judicial Court
for the county of Suffolk, and the appeal was reported by her to
the Appeals Court. After review by the Appeals Court, the
Supreme Judicial Court granted leave to obtain further appellate
review.


     Esther J. Horwich (Stephen J. Wright also present) for the
defendant.
     Kenneth E. Steinfield, Assistant District Attorney, for the
Commonwealth.
                                                                       2


     David R. Rangaviz, Committee for Public Counsel Services,
for Committee for Public Counsel Services, amicus curiae,
submitted a brief.


     GAZIANO, J.    In this case, we confront the scope of two

exceptions to the warrant requirement that have resulted in some

confusion in previous jurisprudence in the Commonwealth:        the

emergency aid exception and the exigent circumstances exception.1

     1.     Background.   a.   Facts.   We summarize the facts found

by the motion judge following an evidentiary hearing on the

defendant's motion to suppress, supplemented by uncontroverted

and undisputed facts in the record that were implicitly credited

by the judge and that do not detract from the judge's ultimate

findings.    See Commonwealth v. Jones-Pannell, 472 Mass. 429, 431

(2015).     We reserve some details for later discussion.

     On the evening of March 4, 2014, the Lawrence police

department received a tip from an unnamed 911 caller.2       The

caller stated that she was "coming down the street" when she saw

two "Spanish guys" "with a gun . . . going up to the building"

located at "7 Royal Street" in a residential neighborhood in

Lawrence.    The caller stated that "they . . . had a hat on," and


     1 We acknowledge the amicus brief submitted by the Committee
for Public Counsel Services.

     2 The record does not contain precise times concerning when
the 911 call occurred or when officers responded to the scene.
Notably, when the officers responded, they were working the
"night shift," which began at 5 P.M. and ended at 1 A.M.
                                                                   3


were wearing "a jacket and a coat," one of which "was gr[a]y and

the other was black."   The caller "heard . . . one of them load

the gun," and saw the men enter the building.   The caller said

that "there's always a little movement in that building," and

acknowledged that she was "not really sure what's going on."      In

addition, the caller stated that she was new to the

neighborhood, and that she had not seen the men previously.     She

provided the dispatcher with her home address, and the

dispatcher indicated to the caller that he was aware of the

caller's telephone number.

     A dispatcher subsequently issued the following report:

"Any detective or any available north car [near the specified

address], caller said she saw two Hispanic males enter a house,

one in a gray jacket, one in a black jacket, the male was

loading gun, was loading a cli[p] to a handgun."3

     The motion judge credited that, during the general period

in which the 911 call was made, the Lawrence police department

was investigating a "rash" of "home invasions" believed to be

the work of a "crew" from New York.   The judge noted, however,

that the evidence did not indicate "how recently or where" the

home invasions had occurred, or if any home invasion had




     3 The judge found that both the 911 caller and the police
dispatcher "provided very general descriptions" of the men who
entered the building.
                                                                    4


"occurred in the immediate vicinity or neighbor[hood] of" the

particular street.

     Multiple police officers responded to the dispatch.      The

address given was one of two numbers associated with a four-unit

apartment building.   The building had a single front door,

marked with the number "5" on the right side of the door and the

number "7" on the left side of the door.   The building contained

two apartments on the ground floor, numbered "5A" and "7A," and

two apartments on the upper floor, numbered "5B" and "7B."     At

the rear of the building, there was a porch with two entrances.

     Sergeant Michael Simard of the Lawrence police department

was the supervising patrol sergeant that evening.   He arrived at

the scene in a marked cruiser and was wearing a uniform.      Simard

saw no one outside the building.   He and a number of other

officers monitored the front entrance.

     Sergeant Joseph Cerullo of the Lawrence police department's

special operations division arrived at the scene in a marked

cruiser; he, too, was wearing a uniform and a badge.4   Cerullo

and four other officers, including two members of the canine

unit of the Essex County sheriff's department, moved to the rear

of the building.




     4 In his role with the special operations division, Sergeant
Joseph Cerullo was responsible for emergency responses.
                                                                    5


     At the front of the building, Simard spoke to residents of

unit 7A, the first-floor apartment located across the hall from

unit 5A.   The residents of unit 7A denied seeing or hearing

anything out of the ordinary, and said that they did not know

who lived in unit 5A.    The residents did describe, however, the

"layout of the apartment [at unit 5A] as far as what door leads

to where."   Simard commented that the residents of unit 7A were

scared because of the "[fifteen] police officers with their guns

drawn."    Simard also stated that, except for the residents of

unit 7A, no residents of the building appeared to be at home.

     After obtaining the telephone number of the 911 caller,

Simard spoke with her by telephone.5   The caller told Simard that


     5 The judge found that the record did not make clear whether
Sergeant Michael Simard spoke first to the residents of unit 7A
or to the 911 caller. We analyze the judge's findings as to
this point based on the record that was before her, and we do
not address later-discovered evidence that the judge did not
consider. Were we to consider this evidence, it would not
change the result we reach.

     At the hearing, the parties stipulated to the admission of
a compact disc (CD) that contained audio recordings captured on
a single audio track. The recordings were of the initial 911
call and the dispatch provided to responding officers. The
judge listened to those recordings; she also was provided a copy
of a CD that contained only those recordings. In its brief to
the Appeals Court, however, the Commonwealth submitted a CD that
contained additional audio recordings of police communications
that had not been before the motion judge, and that were not
transcribed in the filings in the Superior Court or on appeal.
In particular, one of the recordings contains a telephone
conversation between an employee of the Lawrence police
department and the 911 caller that highlights a discrepancy as
to when Simard spoke with the 911 caller. The judge made no
                                                                   6


she had seen three males whom she did not recognize talking on

the front step of the building located at "5-7" on that street.

The caller stated that she had heard the sound of a "rack" being

pulled back on a semiautomatic handgun,6 a sound she recognized

because she was "from Lawrence."   According to Simard, the

caller did not see a firearm.   The caller was nervous, and was

aware of recent armed robberies "in the area."   The judge found

that the "officers at the scene learned the above-described

information within minutes of their arrival."7

     The caller told Simard that the men likely had a key to the

building because they entered the front door "easily."   Cerullo



findings as to that discrepancy, evidence of which was not
before her.
     6 "Racking" a handgun involves pulling the slide back to

load a round into the chamber. See Commonwealth v. Arias, 92
Mass. App. Ct. 439, 447 n.9 (2017). Although the officers did
not determine whether anyone living in the building was licensed
to carry a firearm, the judge credited testimony that a firearms
license check would have taken a significant amount of time.

     7 Cerullo testified that he and Simard "convers[ed] back and
forth" and that Simard shared information he had learned from
the 911 caller. The judge found that "Cerullo and Simard
discussed the information." According to Cerullo, Simard's
"knowledge from the [911] caller was enough for [Cerullo] to
make [his] determination to enter the building" because "[t]he
knowledge of one would be the knowledge of all." It does not
appear, however, that Simard shared all the information he had
learned from the 911 caller. Cerullo testified that he
"possibly heard" that there were "three individuals out front"
of the building, as the 911 caller ultimately told Simard. He
testified also that he was not made aware that those individuals
likely had a key to the building. In any event, Simard, not
Cerullo, ultimately made the decision to enter unit 5A without a
warrant.
                                                                     7


acknowledged that he and the other officers did not consider

whether the men who allegedly entered the building with a

firearm were residents of the building.

     At the rear of the building, Cerullo observed a Hispanic

male leave the building from the left rear door.   The man had

facial hair and was "wearing a black and gray sweater."     He was

identified at the evidentiary hearing as "Wascar Bievenido

Guerrero Diaz."

     With his firearm drawn, Cerullo shouted, "Lawrence Police.

Show me your hands."    From the front of the building, Simard was

able to hear Cerullo.   Diaz appeared "shocked" and "quickly went

back inside" the building, "closing the door behind him."

Cerullo and another officer attempted to enter the building

through the door Diaz had used, but, as the judge determined,

they "found it locked."8   According to Cerullo, the door was

associated with apartment "number 5."   Cerullo did not specify

whether he was referring to apartment 5A, 5B, or both.

     Cerullo moved to the front of the building to discuss the

situation with Simard, while four officers remained at the rear

of the building.   Focusing their attention on unit 5A, Cerullo




     8 The judge did not find that Diaz locked the door to
prevent officers from entering the building.
                                                                    8


and Simard made the decision to enter that unit without a

warrant.9

     Within approximately three to eight minutes after police

arrived at the scene, Cerullo "entered the front door

forcefully," and then led a number of officers through the front

door of the building and into unit 5A.   Conducting a "protective

sweep" for any injured persons and the Hispanic male he had seen

earlier at the rear of the building, Cerullo moved through the

living room toward the rear of the building.   Other officers

searched different areas of the apartment.   They did not find

any people, but they did observe in plain view what appeared to

be illegal narcotics, a scale, and plastic bags strewn on the

floor.   The officers did not seize anything at that point.

     At the rear of the apartment, Cerullo encountered a door

leading to a hallway outside unit 5A.    In the hallway, he saw

another door.   The officers believed that this was the door that

Diaz had used minutes earlier.   Cerullo also saw a stairway

leading up to unit 5B and down to a basement; a light was on in

the basement.   After confirming the absence of any people inside

unit 5A, Cerullo, other officers, and several canine unit dogs

searched the basement; they found and arrested three


     9 The judge found that there was no basis for the officers
to have focused their attention on unit 5A. In addition, the
judge noted that the officers were unaware of anyone who lived
in that apartment.
                                                                      9


individuals.    They did not search anywhere else in the building

for the suspected home invaders.

     Based on observations made during the warrantless search of

unit 5A, officers obtained a search warrant.     Pursuant to the

warrant, they searched unit 5A again and seized items from the

apartment.

     b.   Procedural history.    The defendant filed a motion to

suppress evidence seized pursuant to the warrant, on the ground

that the warrant was predicated on observations made during an

unconstitutional search.     Following an evidentiary hearing, a

Superior Court judge allowed the motion.10    The Commonwealth

filed a petition seeking leave to pursue an interlocutory

appeal, and a single justice of this court allowed the appeal to

proceed in the Appeals Court.     In a split decision, a panel of

the Appeals Court reversed the motion judge, after concluding

that the warrantless search was permissible under the emergency

aid doctrine.     See Commonwealth v. Arias, 92 Mass. App. Ct. 439,

449 (2017).     We allowed the defendant's application for further

appellate review.

     2.   Discussion.    "In reviewing a ruling on a motion to

suppress, we accept the judge's subsidiary findings of fact




     10Although the judge allowed the motion to suppress as to
the defendant and a codefendant, this appeal pertains only to
the defendant.
                                                                    10


absent clear error 'but conduct an independent review of [the

judge's] ultimate findings and conclusions of law.'"

Commonwealth v. Cawthron, 479 Mass. 612, 616 (2018), quoting

Commonwealth v. Scott, 440 Mass. 642, 646 (2004).

    A "warrantless government search of a home is presumptively

unreasonable under the Fourth Amendment to the United States

Constitution and art. 14 of the Massachusetts Declaration of

Rights."    Commonwealth v. Entwistle, 463 Mass. 205, 213 (2012),

cert. denied, 568 U.S. 1129 (2013).     See Kentucky v. King, 563

U.S. 452, 459 (2011); Brigham City v. Stuart, 547 U.S. 398, 403

(2006).    "The presumption against warrantless searches reflects

the importance of the warrant requirement to our democratic

society."   Commonwealth v. Tyree, 455 Mass. 676, 683 (2010).

"Under the exclusionary rule, evidence seized pursuant to an

unreasonable search generally will be suppressed."     Commonwealth

v. Tuschall, 476 Mass. 581, 584 (2017).     "Warrantless searches

may be justifiable, however, if the circumstances of the search

fall within an established exception to the warrant

requirement."   Id.

    a.     Emergency aid exception.   The emergency aid doctrine

establishes one such "narrow exception to the warrant

requirement."   See Commonwealth v. Duncan, 467 Mass. 746, 754,

cert. denied, 135 S. Ct. 224 (2014).     The emergency aid

exception applies when law enforcement officers enter a dwelling
                                                                  11


to provide emergency assistance.   See Commonwealth v. Snell, 428

Mass. 766, 774, cert. denied, 527 U.S. 1010 (1999) (entry is

reasonable under emergency aid exception when made "not to

gather evidence of criminal activity but rather, because of an

emergency, to respond to an immediate need for assistance"

[citation omitted]).

    To fall within the narrowly construed emergency aid

exception, "a warrantless entry and protective sweep must meet

two strict requirements."   See Commonwealth v. Peters, 453 Mass.

818, 823 (2009).    First, at the time of entry, there must be an

objectively reasonable basis for the officers to believe that an

emergency exists.   See Entwistle, 463 Mass. at 213.   Second,

after the entry, the conduct of the officers must be reasonable

under the circumstances, id. at 216; in other words, the search

must not exceed the scope of the emergency.   See Peters, supra.

"Where these two conditions have been satisfied, warrantless

entry into a home is permissible."   Duncan, 467 Mass. at 751.

The "burden rests with the Commonwealth to demonstrate that a

warrantless search . . . fits within the emergency aid exception

to the warrant requirement."   Entwistle, supra at 215, quoting

Peters, supra.   See Snell, 428 Mass. at 774-775.

    i.   Objectively reasonable belief.   To meet its burden, the

Commonwealth first must demonstrate objectively reasonable

grounds to believe that an emergency existed at the time of
                                                                    12


entry.    See Peters, 453 Mass. at 823.   See also Hill v. Walsh,

884 F.3d 16, 19 (1st Cir. 2018) (warrantless entry into dwelling

requires "objectively reasonable basis for believing" that

"immediate aid" is required by someone within [citation

omitted]).

    In determining whether a warrantless entry is objectively

justified, we evaluate it "in relation to the scene as it could

appear to the officers at the time, not as it may seem to a

scholar after the event with the benefit of leisured

retrospective analysis" (citation omitted).    Peters, 453 Mass.

at 825.   A reviewing court does not consider officers'

subjective motivations in entering a house.    See, e.g.,

Entwistle, 463 Mass. at 214.     See also Michigan v. Fisher, 558

U.S. 45, 47 (2009).

    The reasonableness of an entry is evaluated under the

totality of the circumstances.    Compare Tuschall, 476 Mass.

at 585-588 (warrantless entry was unreasonable when fumes

adversely affected neighbor and her pet, but did not threaten

imminent injury, death, or explosion, and there was no

indication anyone inside dwelling required emergency

assistance), with Commonwealth v. Townsend, 453 Mass. 413, 426

(2009) (warrantless entry was reasonable where dwelling was

victim's last known location, her vehicle was parked outside,

she had not been seen or heard from in days, and she had missed
                                                                  13


scheduled visits with her children and her roommate).      See,

e.g., Entwistle, 463 Mass. at 210, 215-216 (warrantless entry

was reasonable where victim had not been seen or heard from in

days, had uncharacteristically missed multiple appointments with

family and friends, and victim's dog could be heard barking

inside house); Snell, 428 Mass. at 768-769, 775 (warrantless

entry was reasonable where victim's vehicle remained parked

outside house for multiple days, victim had not answered

multiple telephone calls from her children, and victim had not

called to wish her son's wife happy birthday).

    Entering officers "do not need ironclad proof of 'a likely

serious, life-threatening' injury," Entwistle, 463 Mass. at 214,

quoting Fisher, 558 U.S. at 49, in order for a warrantless entry

to be reasonable under the circumstances.   In addition, because

the entry is made "to prevent harm stemming from a dangerous

condition, not to investigate criminal activity," a reviewing

court "does not require that police have probable cause that a

crime has been committed."   Tuschall, 476 Mass. at 585.    See

Duncan, 467 Mass. at 750; Hill, 884 F.3d at 23.   It is

sufficient where the totality of the circumstances demonstrates

objectively reasonable grounds to believe that emergency

assistance is needed to prevent imminent physical harm, to

provide assistance to one who is injured, or to protect life or,
                                                                    14


in some circumstances, property.11    See, e.g., Entwistle, supra

at 214, 216.

     ii.    Reasonableness of police conduct inside the dwelling.

To rely upon the emergency aid doctrine, the Commonwealth also

must demonstrate that the conduct of the officers after they

entered the premises was reasonable under the circumstances.

See Entwistle, 463 Mass. at 216.     To be reasonable, the

warrantless conduct of the officers inside the dwelling must be

"strictly circumscribed" by the circumstances of the emergency

that justified entry.    See Commonwealth v. Lewin (No. 1), 407

Mass. 617, 622 (1990), quoting Mincey v. Arizona, 437 U.S. 385,

393 (1978).    Thus, a protective sweep made pursuant to the

emergency aid exception "must be limited in scope to its

purpose," Peters, 453 Mass. at 823, e.g., to preventing imminent

harm, protecting life or property,12 or providing aid to one who

is injured.

     In addition, to be reasonable under the emergency aid

doctrine, the officers' conduct after entry "may not be expanded


     11In Michigan v. Tyler, 436 U.S. 499 (1978), the United
States Supreme Court addressed a narrow context in which
protection of property may support warrantless entry pursuant to
the emergency aid exception. There, the Court held that
firefighters who enter a building to extinguish a fire
"require[] no warrant, and that once in the building, [they] may
remain there for a reasonable time to investigate the cause of
the blaze." Id. at 511.

     12   See note 11, supra.
                                                                     15


into a general search for evidence of criminal activity."      See

Entwistle, 463 Mass. at 217, citing Arizona v. Hicks, 480 U.S.

321, 325 (1987).   See also Lewin (No. 1), 407 Mass. at 622.

Therefore, if, after entry, officers no longer have an

objectively reasonable basis to believe that an emergency

exists, it is unreasonable to continue searching.   See Mincey,

437 U.S. at 393 (warrantless search was unreasonable when

conducted after officers had located all persons in dwelling

during prior protective sweep); Commonwealth v. Kaeppeler, 473

Mass. 396, 403 (2015) ("continued police presence in the

defendant's home without his consent after he was transported to

the hospital for medical treatment and the subsequent seizure of

[evidence in plain view] was unreasonable," because emergency

concerning "the defendant's well-being had ended," and evidence

was seized for "an investigative purpose"); Peters, 453 Mass.

at 820 (warrantless search of dwelling was unconstitutional

after protective sweep eliminated objectively reasonable basis

to believe that emergency existed).

    After completing a protective sweep, however, if officers

continue to have an objectively reasonable basis to believe that

an emergency exists, a subsequent sweep that is limited to the

scope of the emergency may be justified.   See Entwistle, 463

Mass. at 215-219 (two instances of law enforcement entry coupled

with protective sweeps were justified under emergency aid
                                                                  16


exception, because each was supported by objectively reasonable

bases to believe that emergency existed, and officers' conduct

during each sweep was reasonably limited to scope of emergency

at hand); Peters, 453 Mass. at 825 ("We do not declare a 'one

sweep rule'" . . .).

    Undoubtedly, when officers have an objectively reasonable

basis to believe that an emergency exists, and they reasonably

circumscribe the scope of their conduct after entry, "[e]vidence

observed in plain view may be seized," Peters, 453 Mass. at 823,

provided that the officers "have not violated the Fourth

Amendment in arriving at the spot from which the observation of

the evidence is made," King, 563 U.S. at 463; the "incriminating

character" of the evidence is "immediately apparent" (citation

omitted), Kaeppeler, 473 Mass. at 405; and the evidence actually

is in plain view.   See, e.g., Hicks, 480 U.S. at 324-325, 328

("a truly cursory inspection -- one that involves merely looking

at what is already exposed to view, without disturbing it -- is

not a 'search' for Fourth Amendment purposes," but disturbing or

moving objects in plain view constitutes "a 'search'" for which

warrant is required); Entwistle, 463 Mass. at 217 (observation

of content of printed bill fell within scope of emergency aid

exception where "[t]he officer did not open a bill still in its

envelope or search for it in a file or drawer; he merely read
                                                                       17


what was in plain view from an already opened bill that lay on

the kitchen table").

    With these considerations in mind, we turn to the search at

issue.

    iii.     Initial search of unit 5A and basement.   The

defendant maintains that the officers who entered unit 5A and

the basement without a warrant lacked objectively reasonable

grounds to believe that an emergency existed.     The Commonwealth,

for its part, acknowledges an "absence of precedent" justifying

the officers' warrantless entry under the emergency aid

doctrine.

    As the motion judge noted, the "Commonwealth's claim that

the officers had reason for concern that an armed man was

present inside the apartment building is not completely without

merit."     "[P]olice need not wait for screams from within in

order to fear for the safety of occupants or themselves."

United States v. Lenoir, 318 F.3d 725, 730 (7th Cir.), cert.

denied, 540 U.S. 841 (2003).     Entry into unit 5A pursuant to the

emergency aid exception, however, required an objectively

reasonable basis to believe that an emergency existed.       See,

e.g., Fisher, 558 U.S. at 47; Tuschall, 476 Mass. at 585.        The

totality of the circumstances at the time of the entry into

unit 5A did not support such a basis.
                                                                   18


    When the officers arrived at the scene in response to the

911 call, they saw and heard no signs of disturbance, and

detected no signs of forced entry.   To the contrary, they

observed that the doors to the building, and to unit 5A, were

closed and intact.   Moreover, when Simard spoke with the

911 caller, she said that the men had entered the building

"easily," because they likely had a key.    The officers

interviewed residents of unit 7A and learned that the residents,

too, had seen and heard nothing suspicious or out of the

ordinary.   No one else informed the officers of any commotion,

noises, or sounds coming from unit 5A.     As the motion judge

found, the officers had no knowledge of any residents or victims

inside unit 5A, and the only residents of any unit the officers

knew were present were the unharmed residents of unit 7A.

    The fact that Diaz was observed at the back of the building

does not transform the situation into an emergency.    There was

no indication that he was injured, in need of emergency

assistance, armed, or about to harm others, or that he had

harmed others.

    Regardless of whether the officers had sincerely held

beliefs as to the existence of an armed home invasion or hostage

situation, their subjective beliefs at the scene cannot justify

a search under the emergency aid exception.     See, e.g., Stuart,

547 U.S. at 404; Entwistle, 463 Mass. at 214.    The totality of
                                                                    19


the circumstances at the time of entry here did not establish a

reasonable basis to believe that an emergency existed in

unit 5A.13   See Tuschall, 476 Mass. at 585-587.   Therefore, the

warrantless search was not justified under the emergency aid

exception.

     Our analysis does not end there, however.     We turn to

consider whether the entry was justified for some other reason,

i.e., under the probable cause and exigent circumstances

exception.

     b.   Probable cause and exigent circumstances exception.

The judge concluded that, under the exigent circumstances

doctrine, the facts confronting the officers did not establish

the existence of an exigency, or probable cause of an armed home

invasion or hostage situation in progress.

     Pursuant to both art. 14 and the Fourth Amendment, the

exigent circumstances doctrine establishes another "well-

recognized," King, 563 U.S. at 460, yet "narrow" exception to

the warrant requirement, see Tyree, 455 Mass. at 691.    See also


     13As to the second prong of the emergency aid exception,
the reasonableness of the scope of the search, the judge found
that "credible evidence showed that the police conducted only a
limited protective sweep." The defendant argues, however, that
the search of the basement was unreasonable, as the officers had
found no sign of an emergency in unit 5A. Because the officers
lacked an objectively reasonable basis to believe that an
emergency existed anywhere in the building, a protective sweep
was unjustifiable under the emergency aid doctrine, regardless
of the scope of that sweep.
                                                                   20


Commonwealth v. Young, 382 Mass. 448, 456 (1981) ("Exigencies

which may justify a procedure without warrant are a narrow

category and must be established by the Commonwealth . . .");

Commonwealth v. Forde, 367 Mass. 798, 800 (1975) ("the standards

as to exigency are strict").

    "In the absence of a warrant, two conditions must be met in

order for a nonconsensual entry to be valid" under the exigent

circumstances doctrine:   (1) "there must be probable cause" and

(2) "there must be exigent circumstances."   Commonwealth v.

DeJesus, 439 Mass. 616, 619 (2003).   See Figueroa, 468 Mass.

at 211-212.   In this way, "[t]he exigent circumstances exception

to the warrant requirement may be more appropriately denominated

the exception for probable cause and exigent circumstances"

(emphasis in original).   J.A. Grasso, Jr. & C.M. McEvoy,

Suppression Matters Under Massachusetts Law § 14-1[a] (2017).

See Kirk v. Louisiana, 536 U.S. 635, 638 (2002) (per curiam)

("police officers need either a warrant or probable cause plus

exigent circumstances in order to make a lawful entry into a

home").   Put differently, when probable cause exists to believe

that a crime has occurred, is occurring, or will occur

imminently, warrantless entry is justified only if exigent

circumstances also are present.   See Figueroa, supra at 213.

Conversely, without probable cause, the existence of an exigency
                                                                   21


is insufficient to permit warrantless entry into a dwelling.

See id.

       The Commonwealth "bears the burden of proof" to establish

that a warrantless search was proper.    See Young, 382 Mass. at

456.    See also Tyree, 455 Mass. at 684 ("Given the high value

that our Federal and Massachusetts Constitutions assign to the

warrant requirement, particularly in relation to a dwelling, we

impose a heavy burden on the Commonwealth to justify every

warrantless search:    in the absence of consent, the Commonwealth

must prove both probable cause to enter the dwelling and the

existence of exigent circumstances" [footnote omitted]).

       When entry is lawful under the exigent circumstances

doctrine, "the police, in accordance with the rule of 'plain

view,' [may] take into their possession material having apparent

evidential connection to the criminal activity they were in

course of investigating" (footnote omitted).    Young, 382 Mass.

at 458.   See, e.g., King, 563 U.S. at 463 ("[i]t is . . . an

essential predicate to any valid warrantless seizure of

incriminating evidence that the officer did not violate the

Fourth Amendment in arriving at the place from which the

evidence could be plainly viewed" [citation omitted]); Forde,

367 Mass. at 807 ("the police had no legal justification for

being present in the apartment and [therefore] cannot rely on
                                                                     22


the 'plain view' doctrine for a warrantless seizure of

contraband").

       We begin with the question of exigency.

       i.   Exigency.   A warrantless entry is justified only if, in

addition to the existence of probable cause, exigent

circumstances are present.     See Figueroa, 468 Mass. at 213.     See

also King, 563 U.S. at 470 ("Any warrantless entry based on

exigent circumstances must, of course, be supported by a genuine

exigency").     "[A]bsent exigent circumstances, the firm line at

the entrance to the house . . . may not reasonably be crossed

without a warrant" (quotations and citation omitted).      See Kirk,

536 U.S. at 635.

       For exigent circumstances to exist, officers must have

"reasonable grounds to believe that obtaining a warrant would be

impracticable under the circumstances."      Figueroa, 468 Mass.

at 213.     Impracticability arises in the context of the exigent

circumstances doctrine when the delay caused by obtaining a

warrant would create "a significant risk" that "the suspect may

flee," "evidence may be destroyed," or "the safety of the police

or others may be endangered."     Id.   See Tyree, 455 Mass. at 685-

691.

       "In determining whether a warrantless search falls within

the narrow exception of exigent circumstances, we consider 'the

circumstances in their totality' . . ." (citation omitted).
                                                                      23


Figueroa, 468 Mass. at 212.    See King, 563 U.S. at 464.   We

review those circumstances objectively.     See Young, 382 Mass. at

456.    Thus, "whether an exigency existed" is a matter "to be

evaluated in relation to the scene as it could appear to the

officers at the time," not as the scene might appear in

hindsight.   Id.   See Figueroa, supra; DeJesus, 439 Mass. at 620

n.3.    The subjective beliefs or motives of an officer form no

part of this inquiry.    See King, supra.   See also Commonwealth

v. Washington, 449 Mass. 476, 485 (2007).

       In the circumstances here, for the same reasons that the

officers lacked objectively reasonable grounds to believe that

residents of unit 5A were in danger, pursuant to the emergency

aid doctrine, the officers lacked a reasonable basis to believe

that they or others were at risk of imminent harm, pursuant to

the exigent circumstances doctrine.    See Figueroa, 468 Mass.

at 213.   At the scene, officers encountered no indications of

violence or forced entry.     They were unaware of any resident or

victim inside unit 5A.    Indeed, the only residents known to

officers, those of unit 7A, were unharmed, and had neither seen

nor heard anything suspicious.    In addition, when Diaz was seen

at the rear of the building, there was no indication that he,

the police, or anyone else was at risk of imminent injury.       We

therefore agree with the motion judge that there was "nothing
                                                                  24


indicative of an imminent threat of danger to persons inside the

building or to the officers."

    In addition, because the building was surrounded by

officers, there was little risk of a suspect's flight from

within.   See Figueroa, 468 Mass. at 213.   Further, the record

provides no basis for officers to have believed that evidence of

an armed home invasion or hostage situation was at risk of

destruction.   See id. at 214.

    The investigation of a crime, even a serious crime such as

an armed home invasion, does not itself establish an exigency.

See Mincey, 437 U.S. at 394 ("We decline to hold that the

seriousness of the offense under investigation itself creates

exigent circumstances of the kind that under the Fourth

Amendment justify a warrantless search"); id. at 393 ("If the

warrantless search of a homicide scene is reasonable, why not

the warrantless search of the scene of a rape, a robbery, or a

burglary?   No consideration relevant to the Fourth Amendment

suggests any point of rational limitation of such a doctrine"

[quotation and citation omitted]).

    Because officers lacked a reasonable basis to believe that

an exigency existed in unit 5A, the warrantless search was

impermissible.   See DeJesus, 439 Mass. at 620.   Even had the

officers reasonably believed that an exigency existed, for the

warrantless entry to be permissible, there also had to be
                                                                    25


probable cause that a crime was being committed inside the

building.

    ii.     Probable cause.   To justify an entry into a dwelling

pursuant to the exigent circumstances doctrine, the Commonwealth

must demonstrate the existence of probable cause.      See Tyree,

455 Mass. at 684.   "[P]robable cause exists where . . . the

facts and circumstances within the knowledge of the police are

enough to warrant a prudent person in believing that [an]

individual . . . has committed or was committing an offense"

(citation omitted).    Washington, 449 Mass. at 481.    Accordingly,

"an objective test is used to determine whether probable cause

exists."    Commonwealth v. Jewett, 471 Mass. 624, 629 (2015),

quoting Commonwealth v. Franco, 419 Mass. 635, 639 (1995).

    "In dealing with probable cause . . . we deal with

probabilities.    These are not technical; they are . . .

practical considerations of everyday life, on which reasonable

and prudent [people], not legal technicians, act."      Commonwealth

v. Cartright, 478 Mass. 273, 283 (2017), quoting Jewett, 471

Mass. at 629.    "Probable cause does not require . . . that

police [have] resolved all their doubts."     Cartright, supra,

quoting Commonwealth v. Warren, 418 Mass. 86, 90 (1994).

Rather, probable cause "requires more than mere suspicion but

something less than evidence [that would be] sufficient to
                                                                    26


[sustain] a conviction."       Cartright, supra, quoting Jewett,

supra.

       A.   Informant's tip.   Where, as here, police seek to

establish probable cause based on an informant's tip, they must

show, pursuant to the two-prong Aguilar-Spinelli test, both that

the tip is grounded in a basis of knowledge, and that it is

reliable.     See Commonwealth v. Upton, 394 Mass. 363, 375 (1985).

See also Spinelli v. United States, 393 U.S. 410 (1969); Aguilar

v. Texas, 378 U.S. 108 (1964); Commonwealth v. Alfonso A., 438

Mass. 372, 374 (2003).     With respect to informant tips, "the

test for determining probable cause is stricter under art. 14

. . . than under the Fourth Amendment."      Upton, supra at 364.

       In accordance with the Aguilar-Spinelli test, the

Commonwealth first must establish the basis of knowledge

underlying an informant's tip.      See Alfonso A., 438 Mass. at

374; Upton, 394 Mass. at 375.      In general, the basis of

knowledge prong is satisfied where the information provided

springs from an informant's firsthand observations or knowledge.

See Alfonso A., supra.     In addition, where an informant's tip is

sufficiently detailed, a reviewing court reasonably may infer

that the informant had a direct basis of knowledge.      Id. at 374-

375.

       If an informant's basis of knowledge is established, to

justify the warrantless entry, the Commonwealth then must
                                                                   27


demonstrate that the tip was credible.   See Alfonso A., 438

Mass. at 375; Upton, 394 Mass. at 375.   Although a 911 caller's

telephone number may be visible to, or determinable by, the 911

operator, under art. 14, that alone does not demonstrate

sufficiently the reliability of a tip.   See, e.g., Commonwealth

v. Depiero, 473 Mass. 450, 454-455 (2016) (in context of

reasonable suspicion, where showing "less rigorous" than

probable cause is permissible, this court was "not

inclined . . . to attribute veracity to all 911 callers").

Rather, "[w]hen assessing the reliability of [private

individuals] who report apparent violations of the law, we

accord more weight to the reliability of those who are

identified . . . by name and address," because they are not

protected "from the consequences of prevarication that anonymity

would afford, and consequently may be subject to charges of

filing false reports and risk retaliation" (citations omitted).

Commonwealth v. Cavitt, 460 Mass. 617, 628-629 (2011).     See

Depiero, supra at 455 ("The veracity test is more difficult for

the Commonwealth to satisfy where . . . the caller was

anonymous.   Because the caller was anonymous, there could be no

evidence regarding the caller's past reliability or reputation

for honesty" [citation omitted]).

    At the same time, "[i]t is important to recognize that

[private individuals] who report criminal activity justifiably
                                                                      28


may be concerned for their own safety if their identity becomes

known to the persons subsequently investigated or arrested, and

for this reason may wish to remain anonymous."    Cavitt, 460

Mass. at 629.   Such circumstances "should not stand as an

insurmountable impediment to a favorable assessment of [the

informant's] reliability" (citation omitted).    Id.   Therefore,

an unidentified informant who nonetheless is "identifiable" by

officers, see id., and who is aware that officers are able to

identify him or her may receive greater credence than a fully

anonymous informant.   See, e.g., Depiero, 473 Mass. at 455

("even if the police are able to recover the telephone number

and identity of 911 callers, it proves absolutely nothing unless

. . . the anonymous caller was aware of that fact.     It is the

tipster's belief in anonymity, not its reality, that will

control his [or her] behavior" [emphasis in original; quotation

and citation omitted]).

    In addition, the reliability of a tip may be adduced from

the extent to which an informant provides factual details.      See

Alfonso A., 438 Mass. at 375 ("it is especially important that

the tip describe the accused's criminal activity in sufficient

detail that the [court] may know that [it] is relying on

something more substantial than a casual rumor . . . or an

accusation" [citation omitted]).   See also Depiero, 473 Mass.

at 457 ("details provide a level of corroboration beyond that of
                                                                    29


'innocent' or easily obtainable facts"); Alfonso A., supra

at 376 ("While . . . detail, by itself, does not ordinarily

suffice to establish reliability, . . . it remains a factor in

the over-all assessment of the informant's reliability").

    Each prong of the Aguilar-Spinelli test "must be separately

considered and satisfied or supplemented in some way."     Upton,

394 Mass. at 375.     If an informant's tip fails to satisfy both

prongs, other corroborating evidence, such as independent police

corroboration, may be able to "make up for deficiencies in

either or both prongs."     Id. at 376.

    B.   Analysis.    Our inquiry into the issue of probable cause

begins with the 911 call.     We are satisfied that the judge's

subsidiary findings are substantiated by the record.     Although

this case presents a close question of probable cause, we

conclude, as the judge found, that the circumstances confronting

the officers at the scene did not corroborate the caller's tip.

    As to the basis of knowledge prong, we note that the

911 caller informed the Lawrence police dispatcher that she saw

two men "going up to the building" located at the specified

address, and that she heard one of the men load the gun before

he and his companion entered the building.    Thus, the basis of

the 911 caller's firsthand knowledge was apparent from the

initial tip itself.
                                                                    30


    Of course, carrying a firearm is not itself a crime in the

Commonwealth.   See, e.g., Commonwealth v. Alvarado, 423 Mass.

266, 269 (1996).    But loading a handgun in public prior to

entering a residential building does raise valid concerns about

the possibility of imminent criminal conduct.    See Commonwealth

v. Haskell, 438 Mass. 790, 793-794 (2003) (under less stringent

standard for reasonable suspicion, as compared to standard for

probable cause, "the act of publicly loading a handgun is an

event that creates a reasonable suspicion that a crime may be

about to take place").    Thus, the 911 caller claimed to have

seen and heard what could have been criminal activity.

    The more difficult question, however, is whether the

officers had an adequate basis to conclude that the 911 caller's

tip was reliable.    In this regard, the caller provided details

adverse to a determination of probable cause.    She commented

that the men talked calmly before entering the building, which

they entered "easily" because they likely had a key.    In

addition, although she said that she had never seen the men

before, she acknowledged that she was new to the neighborhood

and was unsure of what the men were doing.    The caller also

provided details that, due to their conflicting nature,

undermined her reliability.    She initially said that two men

entered the building, but later told Simard that three men had

entered the building.    Of course, the details provided by the
                                                                     31


caller constitute an important aspect of our assessment of her

reliability.    See Alfonso A., 438 Mass. at 376.   Those details

undercut the reliability of her tip.

    Despite remaining unnamed, however, the 911 caller did give

the dispatcher her home address.    She therefore was aware that

officers could identify her.    See Depiero, 473 Mass. at 455.      In

addition, police had the ability to trace the 911 call to the

caller's telephone number.     Indeed, the dispatcher informed the

caller that her telephone was associated with an address in

Boston.   And Simard ultimately spoke with the caller by

telephone to discuss her observations.     The 911 caller was

therefore aware that another important component of her identity

was known to officers.    We note, however, that "knowledge of the

informant's 'identity' and 'whereabouts,'" are generally

"not . . . adequate standing alone to confirm the informant's

reliability."   See Alfonso A., 438 Mass. at 376.

    As indicated, either prong of the Aguilar-Spinelli test may

be supplemented by corroborating evidence.    See, e.g., Upton,

394 Mass. at 375.   See also Depiero, 473 Mass. at 456 ("the

Commonwealth can . . . establish a caller's reliability through

independent corroboration by police observation or investigation

of the details of the information provided by the caller"

[quotation and citation omitted]).     Because the details of the

911 caller's tip undermined her reliability, the establishment
                                                                   32


of probable cause required independent corroboration.     Here,

however, the officers discovered no corroborating evidence of

criminal conduct; when they did not, the absence of probable

cause became clear.

       As discussed supra, Simard knew that the residents of

unit 7A were unaware of any suspicious activity in unit 5A.

Moreover, he was aware that the men who entered the building did

so "easily," and that this was most likely because they had a

key.    No witness said that there had been any sound or sign of

trouble in unit 5A; and no officer observed any sound or sign of

struggle, violence, forced entry, or damaged property.     We agree

with the motion judge that "nothing . . . indicated that the men

who entered" the building "did not reside there."

       The judge also found that Diaz, who had facial hair and

left the building dressed in a gray and black sweater, did not

match the 911 caller's "very general descriptions of two

Hispanic men" who had entered the building, one of whom wore a

gray jacket and the other of whom wore a black jacket, and

neither of whom had facial hair.    See Commonwealth v. Warren,

475 Mass. 530, 535-536 (2016) ("general description of the

perpetrator and his accomplices" as "two black males

wearing . . . 'dark clothing,' and one black male wearing a 'red

hoodie'" made it unreasonable for police "to target the

defendant or any other black male wearing dark clothing as a
                                                                  33


suspect").   Except for Diaz's gender and ethnicity, he did not

match the 911 caller's general description of the men who had

entered the multiunit apartment building earlier that evening.

Moreover, while the Commonwealth characterizes Diaz's retreat

into the building as evidence of guilt, "evasive conduct in the

absence of any other information," id. at 538, is insufficient

to support probable cause.

    We acknowledge that this case presents a difficult question

of probable cause, and that officers are at times required to

make split-second decisions to avert violence.   The racking of a

firearm in public prior to entering a residential building is

indeed a troubling suggestion of possible violent activity.     In

the circumstances here, however, given the absence of

independent corroborating evidence, the reliability of the 911

caller's testimony was insufficient to establish probable cause

under art. 14.

                                    Order allowing motion to
                                      suppress affirmed.
    LOWY, J. (concurring).          I agree with the court that "the

warrantless search was not justified under the emergency aid

exception."   Ante at       .    I also agree that the search was not

justified under the probable cause and exigent circumstances

exception "[b]ecause officers lacked a reasonable basis to

believe that an exigency existed in unit 5A."          Id. at    .    But

unlike the court, I am convinced that the officers had probable

cause to enter the apartment.

    "Reasonableness must be evaluated in relation to the scene

as it could appear to the officers at the time, not as it may

seem to a scholar after the event with the benefit of leisured

retrospective analysis" (quotation omitted).          Commonwealth v.

Kaeppeler, 473 Mass. 396, 402-403 (2015), quoting Commonwealth

v. Townsend, 453 Mass. 413, 425-426 (2009).         When police act on

information from a private citizen, "the Commonwealth must show

the basis of knowledge of the source of the information (the

basis of knowledge test) and the underlying circumstances

demonstrating that the source of the information was credible or

the information reliable (veracity test)."          Commonwealth v.

Depiero, 473 Mass. 450, 454 (2016), quoting Commonwealth v.

Anderson, 461 Mass. 616, 622, cert. denied, 568 U.S. 946 (2012).

    Here, the court concedes that "the basis of the 911

caller's firsthand knowledge was apparent from the initial tip

itself."   Ante at      .       However, the court then concludes that
                                                                         2


the caller's veracity has not been established.   Id. at             .   I

disagree.

    The court acknowledges that the caller "was aware that

officers could identify her" and that Sergeant Michael Simard of

the Lawrence police department "ultimately spoke with the caller

by telephone to discuss her observations."   Ante at       .    It

then concludes that "'knowledge of the informant's "identity"

and "whereabouts,"' are generally 'not . . . adequate standing

alone to confirm the informant's reliability.'"   Id., quoting

Commonwealth v. Alfonso A., 438 Mass. 372, 376 (2003).     But this

is not a situation in which the police merely knew the

informant's identity.   Nor is it a situation in which the

informant knew theoretically that the police had the ability to

contact her by telephone.   Cf. Commonwealth v. Costa, 448 Mass.

510, 517 (2007) (reliability of caller who knew "that her call

was being recorded, and that the number she was calling from had

been identified, . . . should have been accorded greater weight

than that of an anonymous informant").   Here, police did contact

the informant by telephone, and the informant responded by

continuing to cooperate and by providing significant additional

information.   The caller also used a technical term, "racking,"

to describe what she heard, and she explained that she was

familiar with the sound because of personal experience.        See
                                                                   3


Alfonso A., supra (use of detail "remains a factor in the over-

all assessment of the informant's reliability").1

     This reliable informant told police that she had observed

two men with a gun enter a building at a specified address, and

she claimed to have heard one of the men load a gun.2    It is

unusual for an individual to load a gun on the threshold of a

private residence.   To do so in broad daylight accompanied by

another individual only increases the unlikeliness that the

firearm was being loaded for innocent purposes.     As the court

correctly observes, "loading a handgun in public prior to

entering a residential building . . . raise[s] valid concerns




     1 I assume for purposes of my analysis, as does the court,
that the conversation Sergeant Michael Simard of the Lawrence
police department had with the caller took place before the
officers entered the apartment. A recording with which we were
provided, but to which the motion judge did not have access,
suggests that this conversation might have occurred after the
warrantless entry. See ante at note 5.

     2 The court states that, "[a]ccording to Simard, the caller
did not see a firearm." Ante at     . But according to the
motion judge's factual findings, which we must accept unless
clearly erroneous, "[t]he caller reported that while coming down
her street she observed 'two guys with a gun' at 7 Royal
Street." That finding was not clearly erroneous. Although
Simard testified that the caller never said she had observed a
gun, Sergeant Joseph Cerullo of the Lawrence police department
testified that the caller did say she had observed a gun. The
motion judge was free to credit Cerullo's testimony over that of
Simard. Moreover, the 911 recording, which was played in open
court, confirms that the caller said, "I seen two guys with a
gun."
                                                                       4


about the possibility of imminent criminal conduct."      Ante

at       .

     In addition to having reliable information from the caller

that a gun was being loaded in public, the police also knew

about an ongoing investigation into home invasions in Lawrence.

And when they reached the address that the caller named, a man

emerged from the building, only to retreat inside when an

officer with a drawn gun told him to show his hands.      The police

tried to open the door that the man had reentered, but it was

locked.      There are many reasons why an individual might flee in

the presence of the police.      See Commonwealth v. Warren, 475

Mass. 530, 540 (2016) (observing that black male, "when

approached by the police, might just as easily be motivated by

the desire to avoid the recurring indignity of being racially

profiled as by the desire to hide criminal activity").

Nonetheless, it would seem to be an unusual occurrence when a

person who is told by a police officer with a drawn weapon to

show his hands ignores the command and reenters a residence,

locking the door behind him.      The fleeing man here, combined

with the tip that a gun was being loaded in public and the

knowledge of prior home invasions, gave the police probable

cause.3


     3 That the caller believed the men had a key to the premises
does not alter my conclusion. It is not unusual for a crime in
                                                                   5


    For the foregoing reasons, I concur.




a home to be perpetrated by individuals who know the victims or
have a means peaceably to enter the premises. See Commonwealth
v. Middlemiss, 465 Mass. 627, 629 (2013) (defendant entered
residence with key); Commonwealth v. Morgan, 460 Mass. 277, 285
(2011) (same). See also Commonwealth v. Phap Buth, 480 Mass.
113, 114, cert. denied, 139 S. Ct. 607 (2018) (defendant, who
had previously bought drugs from resident, entered when resident
opened door for him); Commonwealth v. Doucette, 430 Mass. 461,
462-463 (1999) (defendant, who had been resident's friend,
entered through unlocked door).
