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   STATE OF CONNECTICUT v. SAID KENDRICK
                 (SC 18914)
Rogers, C. J., and Palmer, Zarella, Eveleigh, McDonald and Espinosa, Js.
     Argued October 21, 2013—officially released October 21, 2014

  Marjorie Allen Dauster, senior assistant state’s attor-
ney, with whom, on the brief, were David I. Cohen,
state’s attorney, and David R. Applegate, assistant
state’s attorney, for the appellant (state).
  James B. Streeto, assistant public defender, for the
appellee (defendant).
                        Opinion

   ESPINOSA, J. The sole issue in this certified appeal
is whether the Appellate Court properly reversed the
judgment of conviction of the defendant, Said Kendrick,
of criminal possession of a firearm in violation of Gen-
eral Statutes (Rev. to 2007) § 53a-217 (a) (1),1 on the
basis of its conclusion that the trial court improperly
denied the defendant’s motion to suppress evidence
obtained by the police as a result of their warrantless
entry into a bedroom where the defendant was sleeping.
Following our grant of certification,2 the state appeals
from the judgment of the Appellate Court, and claims
that because the police officers reasonably believed
that the warrantless entry into the bedroom was neces-
sary to protect the safety of the officers and others on
the premises, the entry did not violate the defendant’s
rights under the fourth amendment to the United States
constitution. We agree and reverse the judgment of the
Appellate Court.
   The jury reasonably could have found the following
facts. On the evening of May 12, 2008, Detective David
Whipple, a police officer with the Somerset County
Prosecutor’s Office in New Jersey, informed officers in
the Stamford Police Department that New Jersey police
were investigating a homicide, and had reason to
believe that a suspect, Malik Singer, was in the area
of 239 Knickerbocker Avenue in Stamford. Sometime
between 11 p.m. and midnight, after the Stamford police
had received information causing them to focus on the
third floor apartment of the building at that address,
New Jersey and Stamford police officers proceeded to
that third floor apartment, knocked on the door, and
were invited into the apartment by the tenant, Blanca
Valvo. After officers informed Valvo why they were
there, she told them that two African-American males
were in the rear bedroom of the apartment, along with
her daughter, Andrea Valvo, and pointed to the bedroom
door. The New Jersey officers immediately entered the
bedroom, where the defendant was lying in bed with
Andrea Valvo. A second man, James Spurgeon, was
lying on a mattress that was on the floor at the foot of
the bed. The officers ordered the bedroom occupants
not to move, whereupon the defendant lunged toward
an object on the floor near the bed. The police
restrained and handcuffed the defendant and Spurgeon.
After the two men were secured, Sergeant Louis DeMeo
of the Somerset County Prosecutor’s Office searched
the area toward which the defendant had lunged and
discovered a backpack that was partially opened. When
he looked inside, DeMeo saw the handle of a revolver
protruding from a pair of black sneakers inside the
backpack. The Stamford police then took custody of the
backpack, the defendant and Spurgeon. The defendant
subsequently admitted to Whipple that he had received
the backpack and revolver from Singer, who had asked
the defendant to take them with him. The defendant
further admitted that at the time that Singer gave him
the backpack, the defendant knew that it contained
the revolver.
  The defendant was charged with criminal possession
of a firearm in violation of § 53a-217 (a) (1). Following
the court’s denial of the defendant’s motion to suppress,
the parties stipulated to the defendant’s previous felony
conviction, and the case was tried to a jury. The jury
found the defendant guilty, the court rendered judgment
of conviction in accordance with the jury’s verdict, and
the defendant subsequently was sentenced to a two
year mandatory term of imprisonment. State v. Ken-
drick, 132 Conn. App. 473, 475–77, 31 A.3d 1189 (2011).
   The defendant appealed from the judgment of convic-
tion to the Appellate Court, which held that the trial
court had improperly denied the defendant’s motion
to suppress. Id., 475. Specifically, the Appellate Court
concluded that, viewing the evidence under the totality
of the circumstances, ‘‘it was unreasonable for the
police to assume that Singer was present in the apart-
ment or the bedroom and [posed] an imminent threat
of harm to its occupants.’’ Id., 486. Therefore, the Appel-
late Court reversed the judgment of conviction and
remanded the case with direction to grant the defen-
dant’s motion to suppress. Id., 490. This certified
appeal followed.
  The state argues that the Appellate Court improperly
required that there be ‘‘direct evidence’’ that Singer
was present in the apartment in order to justify the
warrantless entry into the bedroom. Although we dis-
agree with the state’s characterization of the Appellate
Court’s rationale, we conclude that viewed under the
totality of the circumstances, the police had a reason-
able belief that exigent circumstances justified the entry
into the bedroom. Specifically, on the basis of the facts
known to the officers at the time that they entered the
bedroom, the police reasonably believed that the entry
was necessary to protect their own safety and the safety
of the occupants.
  The following additional facts are relevant to the
resolution of this appeal. In connection with the shoot-
ing death of a victim whose body was discovered in
New Jersey at 7 a.m. on May 11, 2008, New Jersey police
officers obtained an arrest warrant for Singer, who
police believed had fled the scene of the murder with
a gun in his possession. At the time that New Jersey
police were investigating Singer’s whereabouts, they
had reason to believe that Singer was using a cell phone
that was registered to a person named Ann Marie Petti-
grew.3 Specifically, the girlfriend of an alleged partici-
pant in the murder provided Pettigrew’s cell phone
number to the police, based on her belief that the cell
phone belonged to Singer. Relying on that information,
the police secured a subpoena ordering the cell phone
company to ‘‘ping’’ the cell phone, a process that yielded
a location defined by longitude and latitude.4 Whipple,
who testified regarding the significance of the ping,
initially indicated that a ping identifies ‘‘just a general
area,’’ but later stated that the ‘‘general area’’ is ‘‘within
a certain amount of degree of yards.’’5 Based on the
longitude and latitude, the ping was identified as origi-
nating from 239 Knickerbocker Avenue, a three-story
multifamily home with several small apartments.6
  After New Jersey police officers had conveyed this
information to the Stamford Police Department, Ser-
geant Paul Guzda of the Stamford Police Department
went to Knickerbocker Avenue to investigate. He spoke
to the landlord of 239 Knickerbocker Avenue, who told
him that on the third floor of the building lived a His-
panic woman whose daughter had been keeping com-
pany with an African-American man who fit Singer’s
general description.7
  The police did not obtain either a warrant to search
the third floor apartment at 239 Knickerbocker Avenue
or a warrant for the arrest of the defendant. Instead,
armed with the arrest warrant for Singer, shortly before
midnight on May 12, 2008, a large presence of New
Jersey and Stamford police officers reported to Knicker-
bocker Avenue, including Guzda’s entire squad, numer-
ous police officers from New Jersey, as well as a number
of patrol officers with the Stamford Police Department.
Guzda and Miriam Delgado, a Stamford police officer
who spoke Spanish, ascended the outside staircase to
the third floor, accompanied by numerous Stamford
and New Jersey police officers.8 Although Guzda and
Delgado were in plainclothes, both had their badges dis-
played.
   Witness testimony regarding the interaction between
the police officers and Valvo reveals that the details of
that exchange were in dispute. Although the trial court
made no specific findings regarding these details, in
light of the trial court’s ruling in favor of the state, it
is logical to begin with the assumption that the court
credited the testimony of the state’s witnesses rather
than that of the defendant’s witnesses. Employing that
presumption eliminates some, but not all, of the con-
flicting testimony, because the testimony of the state’s
witnesses was not internally consistent as to all of the
details. Because, however, our review of the record
reveals that the uncontroverted aspects of the testi-
mony of the state’s witnesses supports the ruling of the
trial court, we need not speculate as to how the trial
court might have resolved those inconsistencies, and
we accordingly derive our summary of the facts solely
from the internally consistent testimony of the state’s
witnesses.9
  When one of the officers knocked, Valvo opened the
apartment door. After the officers identified themselves
and told her that they needed to speak to her, Valvo
let them in to the kitchen area.10 The apartment was
very small, with a bedroom toward the back, about ten
to fifteen feet from where the officers were standing,
and another room to the right. The door to the bedroom
was slightly open and the bedroom lights were off. In
response to police inquiries related to their investiga-
tion, Valvo pointed toward the bedroom and indicated
that there were two African-American men in the bed-
room with her daughter.11
   As soon as Valvo indicated that there were two Afri-
can-American men in the bedroom, the New Jersey
officers approached the bedroom door, then knocked
and entered. Whipple was among the New Jersey police
officers who entered the bedroom and identified them-
selves as law enforcement. As they entered the dark-
ened bedroom, one of the officers turned on a light and
Whipple saw the defendant in the bed with a Hispanic
woman, and another African-American man, Spurgeon,
lying on a mattress on the floor at the foot of the bed.
The police instructed the persons not to move, where-
upon the defendant lunged toward something beside the
bed. After Whipple grabbed the defendant, the police
handcuffed both him and Spurgeon. When DeMeo
examined the area toward which the defendant had
lunged, he discovered a partially opened backpack with
a loaded .38 caliber revolver inside. The record does
not reflect that the police recovered the cell phone,
either from the defendant’s person or from the
apartment.
   Preliminarily, we clarify what is not at issue in this
appeal. The defendant does not claim that the police
lacked consent to enter the apartment, and does not
challenge the search of the backpack in which the
revolver was discovered. State v. Kendrick, supra, 132
Conn. App. 478 n.4. He challenges only the warrantless
entry into the bedroom. Additionally, the state does not
contest that the defendant had an expectation of privacy
in the bedroom. Id. Accordingly, the only question pre-
sented in this appeal is whether, once the officers were
in the apartment with Valvo’s consent, their subsequent
warrantless entry into the bedroom violated the defen-
dant’s rights under the fourth amendment to the United
States constitution, or whether that entry was justified
under the exigent circumstances doctrine.
   ‘‘As a general matter, the standard of review for a
motion to suppress is well settled. A finding of fact will
not be disturbed unless it is clearly erroneous in view
of the evidence and pleadings in the whole record
. . . . [W]hen a question of fact is essential to the out-
come of a particular legal determination that implicates
a defendant’s constitutional rights, [however] and the
credibility of witnesses is not the primary issue, our
customary deference to the trial court’s factual findings
is tempered by a scrupulous examination of the record
to ascertain that the trial court’s factual findings are
supported by substantial evidence. . . . [W]here the
legal conclusions of the court are challenged, [our
review is plenary, and] we must determine whether
they are legally and logically correct and whether they
find support in the facts set out in the memorandum
of decision . . . .’’ (Internal quotation marks omitted.)
State v. Boyd, 295 Conn. 707, 717, 992 A.2d 1071 (2010),
cert. denied,       U.S.     , 131 S. Ct. 1474, 179 L. Ed.
2d 314 (2011). Accordingly, the trial court’s legal conclu-
sion regarding the applicability of the exigent circum-
stances doctrine is subject to plenary review.12
   ‘‘Notwithstanding our responsibility to examine the
record scrupulously, it is well established that we may
not substitute our judgment for that of the trial court
when it comes to evaluating the credibility of a witness.
. . . It is the exclusive province of the trier of fact to
weigh conflicting testimony and make determinations
of credibility, crediting some, all or none of any given
witness’ testimony. . . . Questions of whether to
believe or to disbelieve a competent witness are beyond
our review. As a reviewing court, we may not retry the
case or pass on the credibility of witnesses. . . . We
must defer to the trier of fact’s assessment of the credi-
bility of the witnesses that is made on the basis of its
firsthand observation of their conduct, demeanor and
attitude. . . .
  ‘‘[I]f, upon examination of the testimonial record,
the reviewing court discovers but one version of the
relevant events upon which both the state and the defen-
dant agree, and such agreement exists both at trial and
on appeal, the reviewing court may rely on that version
of events in evaluating the propriety of the trial court’s
determinations and determining whether the trial
court’s factual findings are supported by substantial
evidence. In a case where the trial court has concluded
that the police action at issue was justified and the
undisputed version of events reflected in the transcript
was adduced by the state through testimony of the
police officers who were involved, a reviewing court’s
reliance on that version of events is particularly appro-
priate. If the officers’ own testimony as to what
occurred is internally consistent and uncontested by
the defendant but, in fact, undercuts the trial court’s
ruling in favor of the state, a reviewing court would
be remiss in failing to consider it.’’ (Citation omitted;
internal quotation marks omitted.) State v. DeMarco,
311 Conn. 510, 519–20, 88 A.3d 491 (2014).
   ‘‘It is axiomatic that the police may not enter the
home without a warrant or consent, unless one of the
established exceptions to the warrant requirement is
met. Indeed, [p]hysical entry of the home is the chief
evil against which the wording of the fourth amendment
is directed.’’ (Internal quotation marks omitted.) State v.
Ryder, 301 Conn. 810, 821, 23 A.3d 694 (2011). Nighttime
intrusions into the home are examined with particularly
intense scrutiny. Jones v. United States, 357 U.S. 493,
498, 78 S. Ct. 1253, 2 L. Ed. 2d 1514 (1958).
   The trial court analyzed the defendant’s motion to
suppress under the exigent circumstances doctrine, and
we conclude that the doctrine is implicated by the facts
of the present case. Because the trial court’s factual
findings in its ruling on the defendant’s motion to sup-
press are very limited, in summarizing the relevant facts,
we include facts that are implicitly included in the trial
court’s ruling, and we also look to the record for evi-
dence that supports the trial court’s ruling. See, e.g.,
State v. Azukas, 278 Conn. 267, 276, 897 A.2d 554 (2006)
(reading trial court’s decision denying motion to sup-
press to include implicit finding that homeowner had
authority to consent to search of defendant’s bedroom);
State v. Jones, 193 Conn. 70, 79, 475 A.2d 1087 (1984)
(reading trial court’s denial of motion to suppress, in
light of evidence produced at suppression hearing, to
‘‘include implicit findings that the defendant’s parents
had the authority to consent to the searches and did
in fact voluntarily consent’’); see also State v. Martin,
2 Conn. App. 605, 614, 482 A.2d 70 (1984) (The Appellate
Court declined to add facts not found by the trial court,
because ‘‘the court issued a factually detailed memoran-
dum of decision which did not refer to this evidence.
When the court rules on a motion to suppress without
detailing the facts supporting its decision, an appellate
court may look to the evidence produced in support of
the ruling. . . . But where, as here, the trial court per-
forms its judicial function conscientiously by detailing
the facts which the state has established, we are not
free to add facts which are not found and which are
not undisputed.’’ [Citation omitted.]), cert. denied, 195
Conn. 802, 488 A.2d 457, cert. denied, 472 U.S. 1009,
105 S. Ct. 2706, 86 L. Ed. 2d 721 (1985).
   The exigent circumstances doctrine is one of three
exceptions to the warrant requirement that are trig-
gered by the need for swift action by the police. All
three exceptions, the exigent circumstances doctrine,
the protective sweep doctrine and the emergency doc-
trine, must be supported by a reasonable belief that
immediate action was necessary. Because our decisions
have not been entirely clear regarding the distinctions
among the three doctrines, as well as the areas in which
they overlap, we take this opportunity to clarify. Our
decision in State v. Aviles, 277 Conn. 281, 891 A.2d 935,
cert. denied, 549 U.S. 840, 127 S. Ct. 108, 166 L. Ed. 2d
69 (2006), illustrates the ease with which the doctrines
may become confused, and thus, the need for clarifica-
tion. In that case, the defendant had fled the murder
scene after shooting the victim in the chest. Id., 285.
The murder weapon had not been recovered. Id., 295.
The next morning, police officers received information
that the defendant was located in an apartment at 7
Cossett Street in Waterbury. Id., 285. When a police
officer arrived at the apartment, where the defendant
was staying as an overnight guest, a woman opened
the door and invited the officer into the apartment. Id.,
288. When he entered the apartment, the officer ‘‘could
see the defendant through an open doorway in one of
the apartment’s bedrooms.’’ Id. The officer entered the
bedroom, and, although he did not handcuff the defen-
dant, he searched the area of the bedroom within the
immediate reach of the defendant, including under the
bed, for the gun involved in the shooting. Id., 289. It
was undisputed that the officer had not obtained any
warrant, either for the defendant’s arrest, or to search
the apartment. Id., 303. This court, however, took as
its starting point the fact that there was probable cause
to believe that the defendant was the shooter, and the
fact that the officer was lawfully on the premises at the
time that he saw the defendant in the bedroom. Id.,
295. In light of those facts, the issue was whether a
reasonable officer would have believed that exigent
circumstances justified the warrantless entry, that is,
whether the entry into the bedroom was necessary
because absent an immediate arrest, the defendant
could destroy evidence, flee or endanger human life. Id.,
293–95. Although we properly concluded that exigent
circumstances justified the warrantless entry into the
bedroom; id., 295; we inadvertently included in our anal-
ysis a discussion of the emergency doctrine that could
be read to mean that the emergency doctrine and exi-
gent circumstances doctrine are one and the same. Id.,
294. Although it is true that both doctrines are based
on the principle that under certain circumstances the
police must act immediately, we clarify that our deci-
sion in Aviles was grounded on our conclusion that
exigent circumstances justified the warrantless entry
into the bedroom.
   In light of the past confusion in our application of
the exigent circumstances, protective sweep and emer-
gency doctrines, we take this opportunity to clarify the
contours of each doctrine individually, summarizing its
key elements, then highlighting the distinctions and sim-
ilarities of the three doctrines. Of the three, the exigent
circumstances doctrine arguably encompasses the wid-
est variety of factual scenarios. We previously have
recognized the catch-all quality of the doctrine,
explaining that ‘‘[t]he term, exigent circumstances, does
not lend itself to a precise definition but generally refers
to those situations in which law enforcement agents
will be unable or unlikely to effectuate an arrest, search
or seizure, for which probable cause exists, unless they
act swiftly and, without seeking prior judicial authoriza-
tion.’’ (Internal quotation marks omitted.) State v. Gant,
231 Conn. 43, 63–64, 646 A.2d 835 (1994), cert. denied,
514 U.S. 1038, 115 S. Ct. 1404, 131 L. Ed. 2d 291 (1995).
There are three categories of circumstances that are
exigent: those that present a risk of danger to human
life; the destruction of evidence; or the flight of a sus-
pect. State v. Guertin, 190 Conn. 440, 448, 461 A.2d 963
(1983). The exigent circumstances doctrine, however,
is limited to instances in which the police initially have
probable cause either to arrest or to search.
   This court first formally adopted a test for determin-
ing when exigent circumstances justify a warrantless
search or seizure in State v. Guertin, supra, 190 Conn.
448. We considered a number of different tests that had
been adopted in various jurisdictions, and opted for a
broadly worded, totality of the circumstances test; id.,
454; specifically: ‘‘whether, under the totality of the
circumstances, the police had reasonable grounds to
believe that if an immediate arrest [or entry] were not
made, the accused would be able to destroy evidence,
flee or otherwise avoid capture, or might, during the
time necessary to procure a warrant, endanger the
safety or property of others. This is an objective test; its
preeminent criterion is what a reasonable, well-trained
police officer would believe, not what the . . . officer
actually did believe.’’ (Emphasis omitted; internal quo-
tation marks omitted.) Id., 453. Put simply, given proba-
ble cause to arrest or search, exigent circumstances
exist when, under the totality of the circumstances, the
officer reasonably believed that immediate action was
necessary to protect the safety of those present, or
to prevent the flight of a suspect, or the destruction
of evidence.
   In adopting the totality of the circumstances test, we
rejected two distinct tests that expressly would have
required the police either to have a strong or at least
reasonable belief that the suspect was present in order
for exigent circumstances to justify a warrantless entry.
One of those tests is the multifactored test favored by
a number of federal circuit courts, first set forth in
Dorman v. United States, 435 F.2d 385 (D.C. Cir. 1970).
Courts that apply what are known as the ‘‘Dorman
factors’’ consider the following in determining whether
a particular set of circumstances rises to the level of
exigency: ‘‘(1) that a grave offense is involved, particu-
larly one that is a crime of violence; (2) that the suspect
is reasonably believed to be armed; (3) that there is a
clear showing of probable cause; (4) that there is strong
reason to believe the suspect is in the premises being
entered; (5) that there is a likelihood that the suspect
will escape if not swiftly apprehended; (6) that the entry,
though not consented to, is made peaceably, although
forcible entry may be justified in some instances.
Another factor to be considered is (7) the time of entry.’’
(Emphasis added.) State v. Guertin, supra, 190 Conn.
449–50. In rejecting the Dorman factors, we expressed
reservations about the workability of such a rule, which
would require police officers ‘‘to make on-the-spot deci-
sions by a complicated weighing and balancing of a
multitude of imprecise factors.’’ Id., 451, citing 2 W.
LaFave, Search and Seizure § 6.1, p. 390 (1978). The
second test that we considered and rejected in Guertin
was one that had been proposed as an alternative to
the Dorman factors: ‘‘Given probable cause to arrest
and a reasonable belief that the suspect is in his home,
exigent circumstances for a warrantless and noncon-
sensual entry into a suspect’s home to effect this arrest
exist when a reasonably prudent man in the circum-
stances would be warranted in the belief that delay
incident to securing the warrant would pose a signifi-
cant risk of danger to life or property, of the escape of
the suspect, or of the destruction of evidence.’’ (Empha-
sis added; internal quotation marks omitted.) State v.
Guertin, supra, 451. Our rejection of both the Dorman
factors test, as well as the proposed alternate test, in
favor of the totality of the circumstances test, clarified
that no single factor, such as a strong or reasonable
belief that the suspect is present on the premises, will
be determinative in evaluating the reasonableness of a
police officer’s belief that a warrantless entry or arrest
was necessary. Rather than evaluating the significance
of any single factor in isolation, courts must consider
all of the relevant circumstances in evaluating the rea-
sonableness of the officer’s belief that immediate action
was necessary.
   The protective sweep doctrine, like the exigent cir-
cumstances doctrine, is rooted in the investigative and
crime control function of the police. Maryland v. Buie,
494 U.S. 325, 327, 110 S. Ct. 1093, 108 L. Ed. 2d 276
(1990). As its name suggests, the purpose of the doctrine
is to allow police officers to take steps ‘‘to assure them-
selves that the house in which a suspect is being, or
has just been, arrested is not harboring other persons
who are dangerous and who could unexpectedly launch
an attack.’’13 Id., 333. Although originally a protective
sweep was defined as one made incident to a lawful
arrest; id., 334; the scope has since been broadened so
that the current rule is that ‘‘a law enforcement officer
present in a home under lawful process . . . may con-
duct a protective sweep when the officer possesses
‘articulable facts which, taken together with the rational
inferences from those facts, would warrant a reason-
ably prudent officer in believing that the area to be
swept harbors an individual posing a danger to those
on the . . . scene.’ ’’ (Emphasis added.) United States
v. Miller, 430 F.3d 93, 98 (2d Cir. 2005), cert. denied,
547 U.S. 1206, 126 S. Ct. 2888, 165 L. Ed. 2d 916 (2006).
   Courts that have rejected a rule confining valid pro-
tective sweeps to those conducted incident to an arrest
have emphasized that, although the sweep in Buie was
incident to an arrest, the court’s conclusion in Buie
that the search was justified rested on the fact that the
arrest ‘‘exposed the officers to danger.’’ United States
v. Gould, 364 F.3d 578, 581 (5th Cir.), cert. denied, 543
U.S. 955, 125 S. Ct. 437, 160 L. Ed. 2d 317 (2004). Courts
have applied the broadened protective sweep rule set
forth in Buie to uphold sweeps conducted subsequent
to the entry into the home by consent, when the sweep
was supported by a reasonable, articulable suspicion.
See, e.g., id., 587; United States v. Patrick, 959 F.2d
991, 999 (D.C. Cir. 1992).
   The emergency doctrine, unlike the exigent circum-
stances and protective sweep doctrines, is rooted in
the caretaking function of the police. The purpose of
the emergency doctrine is to allow the police to make
a warrantless entry ‘‘to render emergency aid and assis-
tance to a person whom they reasonably believe to be
in distress and in need of that assistance.’’ Root v.
Gauper, 438 F.2d 361, 364 (8th Cir. 1971); see also State
v. Blades, 225 Conn. 609, 616, 626 A.2d 273 (1993). The
police ‘‘must have reason to believe that life or limb is in
immediate jeopardy and that the intrusion is reasonably
necessary to alleviate the threat.’’ (Internal quotation
marks omitted.) State v. Ryder, supra, 301 Conn. 826.
In Blades, we explained that, similar to the exigent
circumstances doctrine, the emergency doctrine justi-
fies a warrantless entry or search when an officer’s
reasonable belief is ‘‘grounded in empirical facts rather
than subjective feelings . . . [and] [t]he test is not
whether the officers actually believed that an emer-
gency existed, but whether a reasonable officer would
have believed that such an emergency existed.’’ (Cita-
tion omitted; internal quotation marks omitted.) State
v. Blades, supra, 618–19. The circumstances set forth
in Blades provide a classic example of facts that impli-
cate the emergency doctrine. In that case, we held that
a warrantless entry into the defendant’s apartment was
justified, where there had been a long history of domes-
tic abuse of the victim by the defendant, concerned
family members reported that the defendant had pro-
vided a false explanation for the victim’s disappearance,
and the police observed a smear of blood on the interior
side of the rear entrance door to the apartment building.
Id., 615–16.
   The protective sweep and exigent circumstances doc-
trines share significant areas of overlap, and some nota-
ble distinctions. Although the exigent circumstances
doctrine allows the police to act upon their reasonable
belief that immediate action is necessary to protect the
safety of those present, or to prevent the flight of a
suspect or the destruction of evidence, the police must
have had probable cause for an arrest or search at the
outset. State v. Guertin, supra, 190 Conn. 447. Thus,
the exigent circumstances doctrine lends itself to a
situation such as in the present case, where the police
reported to the scene to make a planned arrest on a
warrant supported by probable cause, but subsequent
circumstances arose that required them to take action
that was supported only by their reasonable belief. By
contrast, the police may conduct a protective sweep
even in the absence of probable cause to search the
premises or arrest a suspect, as long as the officer is
lawfully present on the premises at the time that the
officer conducts the protective sweep, which of course
must be justified by the officer’s reasonable belief.
   The facts underlying State v. Mann, 271 Conn. 300,
857 A.2d 329 (2004), cert. denied, 544 U.S. 949, 125 S.
Ct. 1711, 161 L. Ed. 2d 527 (2005), aptly illustrate this
principle. In that case, the police knocked on the defen-
dant’s door after receiving a tip concerning drug activity
in that apartment. Id., 303–304. The police were merely
following up on the tip—the state did not claim that
the police were acting upon probable cause to arrest
or search. Id., 306 n.8. In response to the officers’ knock,
the defendant partially opened his door, then attempted
to close it while placing his right hand inside his right
pocket. One of the officers drew his gun, entered the
apartment, conducted a patdown search of the defen-
dant and discovered plastic bags with rock like sub-
stances in them. Id., 304. In holding that the entry was
justified, we relied in part on Buie to conclude that
although there was no probable cause for a search, it
was justified because the officers were legally present
in the hallway, the defendant voluntarily opened the
door, and the defendant’s subsequent actions gave rise
to a reasonable belief that he may be armed. Id., 312–15,
324. We explained that ‘‘[w]e cannot blind ourselves
to the need for law enforcement officers to protect
themselves and other prospective victims of violence
in situations where they may lack probable cause for
an arrest. When an officer is justified in believing that
the individual whose suspicious behavior he is investi-
gating at close range is armed and presently dangerous
to the officer or to others, it would appear to be clearly
unreasonable to deny the officer the power to take
necessary measures to determine whether the person
is in fact carrying a weapon and to neutralize the threat
of physical harm.’’ (Internal quotation marks omitted.)
Id., 318–19, quoting Terry v. Ohio, 392 U.S. 1, 24, 88 S.
Ct. 1868, 20 L. Ed. 2d 889 (1968).
   Because the emergency doctrine is rooted in a differ-
ent function of the police, it stands somewhat apart
from the exigent circumstances and protective sweep
doctrines. That is, although the emergency doctrine,
like the protective sweep and exigent circumstances
doctrines, requires that a search be supported by an
officer’s reasonable belief that immediate action is nec-
essary, the doctrine is rooted in the principle that the
police have a duty to respond to emergencies and
should not be prevented from rendering emergency
assistance when they reasonably believe that such assis-
tance is necessary. This does not mean that there is no
overlap between the emergency doctrine and the other
two doctrines—it is not always a simple matter to delin-
eate precisely pursuant to which function police are
acting in carrying out a particular search or seizure. In
fact, we expressly have acknowledged: ‘‘Police often
operate in the gray area between their community care-
taking function and their function as criminal investiga-
tors. Often there is no bright line separating the one
from the other . . . .’’ State v. Blades, supra, 225 Conn.
619. In many instances, however, it is possible to discern
whether the police are acting in their crime control or
investigative functions, or instead are acting pursuant to
their community caretaking function. That distinction,
which depends on the particular facts of the case, will
determine whether the emergency doctrine applies, as
opposed to either the exigent circumstances doctrine
or protective sweep doctrine.
   In the present case, because the police had an arrest
warrant for Singer, supported by probable cause, the
trial court properly applied the exigent circumstances
doctrine in analyzing the defendant’s motion to sup-
press.14 The question presented, then, is whether, under
the totality of the circumstances, a reasonable, well
trained police officer reasonably would have believed
that immediate entry into the bedroom was necessary to
protect his own safety and the safety of others present in
the apartment. See State v. Guertin, supra, 190 Conn.
453. We must evaluate the reasonableness of the offi-
cers’ belief in light of the speed with which events were
unfolding, and on the basis of the facts known to them
at the time that they were standing in Valvo’s kitchen
and she informed them that ten to fifteen feet away
from them, behind a partially open door, were two
African-American males. Those facts include that there
was probable cause to believe that Singer had commit-
ted a homicide within the past two days, and that he
was on the run. The murder weapon, a gun, had not
been found at the scene of the crime, so police reason-
ably could have believed that Singer had taken it with
him. It is highly significant that the police had traced
to that address a cell phone that a witness told them was
being used by Singer. That single piece of information
limited the scope of the search to a very small area—
the apartment units within the building at 239 Knicker-
bocker Avenue. The landlord of the building had
informed police earlier that evening that an African-
American man matching Singer’s general description
had been ‘‘keeping company with’’ the daughter of the
tenant in the third floor unit. The information provided
by the landlord must be understood in conjunction with
the information provided by the cellular ping. Specifi-
cally, despite the lack of detail provided by the landlord,
his information must be understood as merely nar-
rowing the scope of the search further, from the very
small target area of 239 Knickerbocker Avenue. The
only question remaining at that point in time was in
which unit were the police most likely to find the sus-
pect. In evaluating the reasonableness of the officers’
conclusion that the suspect was in the bedroom, we
also must consider Valvo’s statement to the police that
there were two African-American men in the bedroom
at that very moment.15
   Accordingly, once the police had the information
from the cellular ping, the pool of potential suspects
was not African-American men generally, or even Afri-
can-American men within the city of Stamford, but Afri-
can-American men at that particular address. There is
no indication in the record that the landlord identified
any other African-American men associated with any
of the units at 239 Knickerbocker Avenue. Viewed in
that light, the landlord’s information, which by itself
clearly would have been insufficient subsequently to
support a reasonable belief that immediate entry into
the bedroom was necessary to protect those present,
provided an important piece of additional information
by narrowing the target area to the third floor unit.
Finally, when they entered Valvo’s apartment to investi-
gate further, they learned that there were two African-
American men behind the partially open bedroom door,
which was close enough to where they stood that who-
ever was behind the door could have heard the entire
conversation that the police had with Valvo.
   Viewed under the totality of the circumstances, we
conclude that the trial court properly concluded that
exigent circumstances justified the entry into the bed-
room. The officers reasonably believed that the entry
was necessary for their own protection, as well as the
protection of others in the apartment. We emphasize
that although the level of certainty that officers had
regarding the presence of Singer or some person associ-
ated with him in the bedroom is relevant to our inquiry,
we examine that question in light of the overall question
of whether it was reasonable for the police to believe
that immediate entry into the bedroom was necessary
to protect the safety of those present. We also empha-
size that it was unnecessary for the officers to have a
level of certainty approaching probable cause to believe
that Singer or an associate was present in the apart-
ment. It was sufficient that the facts known to them at
the time would support a reasonable belief that a person
or persons in the bedroom—either Singer or a person
connected to him—posed a threat of danger to the
officers and others present.
   That standard is satisfied in the present case. In that
small apartment, with the information that the police
had available to them, it would have been unreasonable
and dangerous for the police to fail to take the final
step of entering the bedroom to neutralize Singer or an
associate, before that person could threaten the safety
of the officers and others present in the apartment. The
United States Supreme Court has recognized that ‘‘[t]he
calculus of reasonableness must embody allowance for
the fact that police officers are often forced to make
split-second judgments—in circumstances that are
tense, uncertain, and rapidly evolving.’’ (Internal quota-
tion marks omitted.) Kentucky v. King,        U.S. , 131
S. Ct. 1849, 1860, 179 L. Ed. 2d 865 (2011). The factual
circumstances known to the officers at the time of the
warrantless entry in the present case constituted pre-
cisely the type of circumstances envisioned by the
United States Supreme Court. As Guzda testified at trial:
‘‘We’re looking for somebody who supposedly had a
handgun. For everybody’s safety, we’re gonna check
that apartment. I’m not gonna wait to get shot through
a door, when he hears that we’re out there.’’
   We find unpersuasive the defendant’s contention that
the information relied upon by the police was insuffi-
cient to support a reasonable belief that immediate
entry into the bedroom was necessary. Specifically, the
defendant contends that the information available to
the police at the time of the warrantless entry did not
rise to the level of ‘‘specific and articulable facts’’
required to support a reasonable belief that immediate
entry was necessary. See Terry v. Ohio, supra, 392 U.S.
21. Put another way, the defendant argues, the police
did not have sufficient information to support a reason-
able belief that Singer was in the bedroom. As we
already have indicated, however, the police had suffi-
cient information to support precisely that reasonable
belief. The police methodically, in a very short time
period, followed a logical chain of clues that pointed
to the presence of Singer in the third floor apartment at
239 Knickerbocker Avenue, beginning with the cellular
ping, then to the landlord’s information, and finally to
Valvo’s statement that there were two African-American
men behind the bedroom door. Standing alone, none
of these pieces of evidence would suffice to support
the officers’ reasonable belief, but we must view
them together.
   The defendant’s argument in support of this con-
tention is three-pronged. He challenges the value of the
cellular ping, claims that the landlord’s description was
too vague, and relies on disputed facts regarding the
exchange that occurred between Valvo and the police.
As to the ping and the landlord’s description, the defen-
dant claims that the cell phone was pinged hours before
the police arrived. As we already have observed; see
footnote 5 of this opinion; the record does not reflect
when the ping occurred, and the most that the trial
court could have inferred is that it occurred sometime
after the cell phone number was provided to police and
before Whipple relayed the information from the ping
to the Stamford police. The defendant also suggests
that the police improperly relied on the witness’ state-
ment that Singer was using the cell phone in question
at the time, despite the fact that the cell phone was not
registered to Singer. He also questions the inference
drawn by the police that Singer would have retained
the cell phone when he fled. He additionally points to
the vagueness of the landlord’s description, which was
merely that a black male was associated with the third
floor unit. The defendant seeks a level of certainty not
required by the law. Certainly, if the police had asked
the cell phone company to perform a subsequent ping
immediately prior to entering the apartment, yielding
the same address, if the cell phone had been registered
to Singer rather than to Pettigrew, and if the landlord
had described the man associated with the third floor
apartment as a light-skinned, African-American male,
approximately five feet, ten inches tall, with teardrop
tattoos on his face, the police would have had a level
of certainty approaching probable cause to believe that
Singer was present in the apartment. But our law
requires only a reasonable belief when exigent circum-
stances are present. As we have explained, the informa-
tion available to the police at the time they entered
the bedroom was sufficient to satisfy that standard.
Regarding the defendant’s reliance on disputed facts in
the exchange between the police and Valvo, the defen-
dant points only to those facts that would not support
the trial court’s ruling on the motion to suppress. That
reliance is not consistent with the standard of review
on a motion to suppress.
   Finally, the defendant also argues that in order for
the exigent circumstances doctrine to apply, the state
bore the burden to establish that there was insufficient
time to secure a search warrant for the apartment. The
defendant’s argument, which ignores the fact that the
police were lawfully in Valvo’s apartment with her con-
sent at the time that the exigency arose, is one that we
rejected in State v. Aviles, supra, 277 Conn. 303, where
we explained that ‘‘even if we were to assume that the
police could have obtained an arrest and search warrant
for the defendant prior to [the police officer] entering
the premises, this fact does not mean that their failure
to do so necessarily invalidates the warrantless conduct
that followed. We reach this conclusion because, by
obtaining consent to enter the apartment, [the police
officer] was already lawfully in a position to observe
the exigent circumstances that justified his further
actions.’’ Similarly, in the present case, the police were
lawfully present in the apartment when they became
aware of the circumstances justifying the warrantless
entry into the bedroom.
  The judgment of the Appellate Court is reversed and
the case is remanded to that court with direction to
render judgment affirming the judgment of the trial
court.
  In this opinion ROGERS, C. J., and ZARELLA and
EVELEIGH, Js., concurred.
  1
    Hereinafter, unless otherwise indicated, all references to § 53a-217 are
to the 2007 revision of the statute. Although the judgment file indicates that
the defendant was convicted of criminal possession of a pistol or revolver
in violation of General Statutes (Rev. to 2007) § 53a-217c, that appears to
have been a scrivener’s error. The long form information charged the defen-
dant with a violation of § 53a-217 (a) (1); the court consistently instructed
the jury during trial that the defendant was charged with violating § 53a-
217 (a) (1); and the jury’s verdict found the defendant guilty of violating
§ 53a-217 (a) (1). At sentencing, the court mistakenly referred to General
Statutes (Rev. to 2007) § 53a-217c, but the court imposed the mandatory
minimum sentence of two years required under § 53a-217 (b), which clarifies
that the statute under which the defendant was convicted was § 53a-217,
not General Statutes (Rev. to 2007) § 53a-217c, which does not specify a
mandatory minimum sentence.
  2
    This court granted the state’s petition for certification to appeal, limited
to the following question: ‘‘Did the Appellate Court properly determine that
the trial court improperly denied the defendant’s motion to suppress based
upon the exigent circumstances of a warrantless entry?’’ State v. Kendrick,
303 Conn. 925, 925–26, 35 A.3d 1076 (2012).
   3
     Prior to the defendant’s arrest, New Jersey police did not have any
information regarding Pettigrew’s identification. The record is somewhat
unclear as to who she is. Whipple testified that police subsequently had
learned that Pettigrew is the defendant’s mother, but the trial court stated
in its memorandum of decision that she is Singer’s mother.
   4
     The record does not reveal any details regarding the precise nature of
a cellular ping, the technology involved, or its accuracy. No expert testimony
was offered, and Whipple acknowledged during his testimony that he was
not an expert on cell phone technology or the process of ‘‘ping[ing]’’ a
cell phone.
   5
     The record does not reveal when the cell phone company performed
the ping. The trial court properly could have inferred, however, that the
cell phone company could have performed the ping only after the witness
provided Pettigrew’s cell phone number to the New Jersey police—which
must have occurred sometime after the victim’s body was discovered on
the morning of May 11, 2008—and sometime before Whipple spoke to the
Stamford police on May 12, 2008.
   6
     The defendant relies on two items of testimony offered during trial that
he claims conflict with Whipple’s testimony during the suppression hearing
that the cellular ping defined a target area within a few yards. Although the
testimony that the defendant points to was not presented at the suppression
hearing, we review the record in its entirety to determine whether a defen-
dant’s constitutional rights were infringed by the denial of a motion to
suppress. See State v. Fields, 265 Conn. 184, 191, 827 A.2d 690 (2003); State
v. Toste, 198 Conn. 573, 576, 504 A.2d 1036 (1986). The mere fact that some
of the testimony on which the defendant relies could have supported a
ruling contrary to the trial court’s ruling on the motion to suppress, however,
does not require reversal. While it is true that we scrupulously examine the
record when ‘‘a question of fact is essential to the outcome of a particular
legal determination that implicates a defendant’s constitutional rights . . .
and the credibility of witnesses is not the primary issue,’’ our inquiry is
aimed at discerning whether there is substantial evidence to support the
trial court’s ruling. State v. Boyd, 295 Conn. 707, 717, 992 A.2d 1071 (2010),
cert. denied,       U.S. , 131 S. Ct. 1474, 179 L. Ed. 2d 314 (2011).
   The defendant relies on the testimony of Sergeant Paul Guzda of the
Stamford Police Department and DeMeo at trial. Specifically, during cross-
examination, Guzda stated that the information that the New Jersey police
provided to the Stamford police regarding the area yielded by the cellular
ping ‘‘initially . . . may have been more general.’’ He immediately clarified,
however, that ‘‘when we finally made our decision to go [to 239 Knicker-
bocker Avenue], most of the information came from one of the [New] Jersey
officers.’’ Reading Guzda’s testimony in its entirety, therefore, reveals that
he stated that the information that he received from the landlord at that
address did not ‘‘narrow down’’ the initial target area identified by the ping.
Instead, the landlord’s statement merely ‘‘reaffirmed’’ the information that
the New Jersey police had conveyed, namely, that on the basis of the ping,
they believed that Singer was located at 239 Knickerbocker Avenue. Guzda’s
trial testimony, therefore, is consistent with Whipple’s testimony at the
suppression hearing.
   DeMeo’s testimony is inconsistent with the implicit finding of the trial
court that the cellular ping limited the search area to 239 Knickerbocker
Avenue. Like Whipple, DeMeo prefaced his statements by admitting that he
is not an expert on the process of pinging a cell phone. DeMeo suggested
that a cellular ping yields a location narrowed ‘‘down to a street’’ and that
the identification of a more precise location requires investigative follow
up. The trial court, however, was free to credit the testimony of other
witnesses, specifically, Whipple and Guzda, who testified that the cellular
ping limited the search area to 239 Knickerbocker Avenue, and that subse-
quent police investigation merely confirmed that information and narrowed
the target area down further to the third floor unit. The testimony of those
two witnesses provides substantial support for the trial court’s ruling.
   7
     Both the defendant and Singer are African-American. The precise nature
of the description that Guzda provided to the landlord is not clear from
the record. On cross-examination, he acknowledged that he did not ‘‘feel
comfortable sharing too much’’ information with the landlord. He also admit-
ted that the description that he provided could have fit numerous black men.
   Whipple testified that while the New Jersey police were en route to
Stamford, he contacted the Stamford Police Department and described
Singer as a black male, approximately five feet, ten inches tall, with facial
tattoos, but neither he nor Guzda testified that this description was communi-
cated to Guzda in particular, or that Guzda provided this description to the
landlord. It is undisputed that the New Jersey police did not provide a
photograph of Singer to the Stamford police before they arrived in Con-
necticut.
   8
     Although the focus of the investigation at that point in time was the
apartment on the third floor, the police officers knocked on the doors to
all of the apartments in the building that night.
   9
     We additionally observe that the defendant did not file a motion for
articulation seeking to have the trial court clarify any findings it had made
that may have resolved the inconsistencies.
   10
      Although Valvo disputed at trial that she consented to the officers’ entry
into the apartment, the defendant does not contest this issue on appeal.
   11
      As we have explained, the remaining details regarding the exchange
between the police and Valvo were in dispute. There were four different
accounts. Guzda testified that when he and Delgado entered the apartment,
they questioned Valvo, asking her whether she knew Singer, and she
responded that she did not recognize the name and did not know what they
were talking about. She also responded, however, that her daughter was in
the bedroom with two African-American men. Guzda expressed doubt, when
pressed, that anyone would have had time to show Valvo a photograph of
Singer before the police entered the bedroom.
   By contrast, Whipple testified that after they explained to Valvo that they
were looking for Singer, he showed her a photograph of Singer. He did not
recall that Valvo responded that she did not know Singer, just that she
pointed toward the bedroom door and stated that her daughter was in there
with two African-American men. Whipple also testified that Valvo gave the
police permission to enter the bedroom.
   Delgado testified that she questioned Valvo, and asked her who lived in
the apartment with her. When Valvo replied that her daughter lived there,
Delgado asked if the daughter was home at that time. Valvo responded
yes, with two friends. When Delgado asked who the friends were, Valvo
responded that they were two black males, then she pointed to the bedroom.
   Valvo testified that when the police entered the apartment, they showed
her several photographs of individuals, and when she responded that she
did not recognize the individuals in those photographs, the police showed
her a photograph of the defendant. She indicated that she knew the defendant
and when they asked where he was, she pointed to the bedroom door.
   12
      The defendant argues that this court must review the decision of the
Appellate Court for abuse of discretion. The defendant relies on our decisions
that have stated that ‘‘in a certified appeal, the focus of our review is not
the actions of the trial court, but the actions of the Appellate Court. We do
not hear the appeal de novo.’’ (Internal quotation marks omitted.) State v.
Saucier, 283 Conn. 207, 221, 926 A.2d 633 (2007). Apparently, the defendant
reads our statement that we do not hear the appeal ‘‘de novo’’ to mean that
the abuse of discretion standard applies to our review of the Appellate
Court’s decision. That reading is incorrect. The statement merely means
that ‘‘[t]he only questions that we need consider are those squarely raised
by the petition for certification, and we will ordinarily consider these issues
in the form in which they have been framed in the Appellate Court.’’ (Internal
quotation marks omitted.) Id.
   13
      For a protective sweep of the immediate area surrounding an arrestee,
an officer does not need either probable cause or reasonable suspicion as
such a sweep is justified as a precautionary measure. Maryland v. Buie,
supra, 494 U.S. 334.
   14
      We observe that because the officers entered the bedroom on the basis
of their belief that immediate action was necessary to protect themselves
and others in the apartment, and because the facts supporting that belief
became known to the officers when they were lawfully present in the apart-
ment, the protective sweep doctrine was also implicated by the facts of the
case. The emergency doctrine was not implicated.
   15
      Although we recognize that the ping was significant, the dissent places
too much emphasis on that single piece of information. We must analyze
the propriety of the entry into the bedroom on the basis of all of the
information available to the police at the time that they were standing in
Valvo’s kitchen. As our analysis demonstrates, at that time, the ping was
but one of a multitude of pieces of information that the police relied on to
support their reasonable suspicion that Singer or one of his associates was
behind the partially opened bedroom door. The dissent mistakenly focuses
on what the trial court did not know about the ping itself, and accordingly
suggests that our focus should be on the information that the police did
not have at the time that they entered the bedroom. To the contrary, our
inquiry properly focuses on what information the police did have at the
time of entry. Considering all of the facts known to the police, namely, the
evidence that Singer had shot a man to death less than forty-eight hours
prior to the search and was at large with the murder weapon, the ping,
the information provided by the landlord, and the confirmation of that
information by Valvo’s statements, we conclude that even without the ping,
the police would have had enough information—at the time that they were
standing in Valvo’s kitchen—to support their reasonable suspicion that
Singer or one of his associates was behind the bedroom door.
