                 FOR PUBLICATION
 UNITED STATES COURT OF APPEALS
      FOR THE NINTH CIRCUIT

UNITED STATES OF AMERICA,             
               Plaintiff-Appellant,         No. 04-10041
                v.
                                             D.C. No.
                                          CR-01-01696-RCC
GONZALEZ, INC. dba GOLDEN STATE
TRANSPORTATION,                              OPINION
              Defendant-Appellee.
                                      
       Appeal from the United States District Court
                for the District of Arizona
        Raner C. Collins, District Judge, Presiding

                 Argued and Submitted
       December 7, 2004—San Francisco, California

                    Filed June 22, 2005

   Before: Dorothy W. Nelson, Andrew J. Kleinfeld, and
            Ronald M. Gould, Circuit Judges.

              Opinion by Judge D.W. Nelson




                           7425
               UNITED STATES v. GONZALEZ, INC.            7429


                         COUNSEL

Bruce M. Ferg, (argued); Paul K. Charlton and Christina M.
Cabanillas (on the briefs), Office of the U.S. Attorney, Tuc-
son, Arizona, for the plaintiff-appellant.

William Kirchner (argued) and Walter Nash (on the briefs),
Nash & Kirchner, P.C., Tucson, Arizona; Jefferson Keenan
(on the briefs) and Michael Piccarreta (argued), Piccarreta &
Davis, P.C., Tucson, for the defendants-appellees.


                         OPINION

D.W. NELSON, Circuit Judge:

   The government appeals the district court order granting in
part defendants’ motion to suppress evidence obtained as a
result of wiretaps at the Los Angeles headquarters of Gonza-
lez, Inc., dba Golden State Transportation (GST). We con-
sider below whether the district court erred by: (1) conducting
a hearing pursuant to Franks v. Delaware, 438 U.S. 154
(1978); (2) finding that the wiretap issued for the company
headquarters failed to meet the statutory necessity require-
ment; and (3) granting standing to Antonio and Francisco
Gonzalez to challenge all conversations intercepted under the
invalidated wiretap order. We conclude that each of the dis-
trict court’s rulings was correct, and thus we affirm.

     FACTUAL AND PROCEDURAL BACKGROUND

   This appeal involves a multi-year investigation into an
alleged conspiracy to smuggle aliens into the United States
7430           UNITED STATES v. GONZALEZ, INC.
using a public bus company, GST. Although the government
received and acted upon reports of alien smuggling at GST as
early as May 1996, a sustained federal investigation into the
alleged smuggling ring facilitated by GST did not begin until
1999. At that time, GST had bus terminals in nine western
states.

   Initially, the investigation focused on GST’s Arizona oper-
ations. During this stage, federal agents employed several tra-
ditional investigative methods. For example, agents used pole
cameras to conduct about 25,000 hours of video surveillance
at the Tucson and Phoenix bus terminals and at a Tucson
motel believed to be an alien safe house. In addition, agents
in parked cars conducted 2,000 hours of physical surveillance
near the two terminals. Undercover agents were widely used
to gain an understanding of what occurred inside the terminals
and on the buses. Two undercover agents became GST bus
drivers, and one of these agents later worked at the Tucson
terminal selling bus tickets and handling baggage. Undercover
agents also posed as both undocumented aliens on GST buses
and as smugglers at GST terminals. Other undercover agents
infiltrated an alien-smuggling organization by picking up
aliens near the border and taking them to the Tucson terminal.
As a result of these successful efforts, agents engaged in, and
even recorded, many conversations implicating GST employ-
ees in alien-smuggling activities. The government also
recruited confidential informants (CIs) from GST’s past and
current employees, including a current dispatcher at the Tuc-
son terminal and a bus driver. These CIs provided company
documents and valuable information to aid the government
investigation. Finally, the government also utilized pen regis-
ters and trap-and-trace devices to gather information in the
Arizona-centered investigation.

  After this intensive investigation into the activities at the
Phoenix and Tucson terminals, the government applied for a
wiretap order of these terminals’ telephones (hereafter “Ter-
minal wiretap”). On April 2, 2001, the district court issued an
                UNITED STATES v. GONZALEZ, INC.            7431
order authorizing the Terminal wiretaps. After this authoriza-
tion, the government conducted immigration stops of approxi-
mately thirteen GST buses departing from the terminals to
generate chatter among the suspected conspirators. The gov-
ernment intercepted a phone call made by Francisco Gonza-
lez, the founder and vice president of GST, from the
company’s headquarters on Blake Avenue in Los Angeles.
During this call Francisco discussed the immigration stops of
GST buses from the Tucson and Phoenix terminals. On May
4, 2001, the government applied for, and was granted, a 30-
day extension of the Terminal wiretap. During this extension
the government intercepted an additional telephone conversa-
tion between Francisco and a Phoenix terminal employee
where Francisco inquired if the terminal had “been bothered
anymore,” presumably by immigration.

   On May 30, 2001, the government applied for a wiretap of
GST’s Blake Avenue office in Los Angeles, which the district
court granted (hereafter “Blake Avenue wiretap”). Special
Agent Richard Hill of the U.S. Border Patrol, supplied an affi-
davit in support of this application. A key purpose of the
Blake Avenue wiretap was to intercept incriminating evidence
linking Francisco, his son Antonio Gonzalez, and others in the
Blake Avenue office to the alleged alien-smuggling ring. At
the time, Antonio was the president and chief operating offi-
cer of GST. According to Hill’s affidavit, prior to the Blake
Avenue wiretap, the government had intercepted only two
telephone calls from Antonio, which merely “indicate[d] that
Antonio was aware of law enforcement action in which
undocumented aliens were removed from [GST] buses and
that he conversed with his father [(Francisco)], brother and
managers regarding the corporate activities.” In contrast, the
government had intercepted “[s]everal calls” from Francisco
during which he “discussed the movement of people on his
buses and routinely asked about intervention from immigra-
tion and local law enforcement.”

  On either July 13 or 14, 2000, long before the government
requested any wiretaps as part of this investigation, one of the
7432            UNITED STATES v. GONZALEZ, INC.
government’s CIs, a GST bus driver, visited the Blake Ave-
nue office unannounced and engaged Francisco in conversa-
tion while wearing a wire. During the conversation, the
informant questioned Francisco about a recent company
memorandum requiring drivers to check for undocumented
aliens on their buses. Francisco insinuated that the memoran-
dum did not refer to the prearranged smuggling of undocu-
mented aliens from Tucson, but rather to unauthorized aliens
who may sneak onto GST buses coming over the border. The
same CI returned, at the government’s request, to the Blake
Avenue office to speak with Francisco again that same day.
This time the CI more directly questioned Francisco about the
smuggling of aliens using GST buses. Neither of these
recorded conversations was reported in any of the govern-
ment’s affidavits supporting any of its wiretap requests.

   As acknowledged in the Hill affidavit, the government con-
ducted limited investigation into activities at the Blake Ave-
nue office before seeking the Blake Avenue office wiretap.
This brief investigation included: five-days of pen registers on
the office’s telephones; an equally brief use of trap-and-trace
analysis of the telephones; limited physical surveillance; and
a preliminary inquiry attempting to place an undercover agent
at one of the company’s “Los Angeles offices,” which might
have included the Blake Avenue office.

   Agent Hill’s affidavit for the Blake Avenue wiretap stated
that “[p]hysical [s]urveillance has been attempted at the head-
quarters but was not successful” because the building’s layout
and proximity to a residential neighborhood precluded agents
from gathering this evidence. The affidavit also deemed fur-
ther physical surveillance impractical based on “what may
have been a counter-surveillance effort” in which agents were
once briefly followed by a vehicle after leaving the surveil-
lance site.

  Despite the success of video surveillance earlier in this
investigation, the Blake Avenue affidavit stated that a pole
                  UNITED STATES v. GONZALEZ, INC.                 7433
camera or other video surveillance of the office was not
attempted because any effort would fail to “reveal the corpo-
rate transactions relating to illegal activities occurring inside”
the building.

   Agent Hill also claimed in his affidavit that “[u]ndercover
agents have been used extensively throughout this investiga-
tion,” but goes on to make clear that none of these agents
infiltrated the Blake Avenue building. Despite the fruitful evi-
dence produced by undercover agents in the terminal investi-
gation, Agent Hill averred that prior to the Blake Avenue
wiretap application only a lone attempt was made to infiltrate
“one of [GST’s] Los Angeles offices.” The affidavit does not
indicate whether this infiltration attempt was focused, like the
earlier efforts, on a terminal in the Los Angeles area or on the
Blake Avenue office itself. On the face of the affidavit, the
repeated description of this infiltration attempt as being tar-
geted to “one of the Los Angeles offices” as opposed to “the
Los Angeles office” or even the “Blake Avenue office” makes
it impossible for an issuing court to have concluded that this
infiltration attempt was focused on the Blake Avenue office.1

   Based on the record created in the Franks hearing, we do
know that one undercover agent was able to speak with Fran-
cisco, but could not engage him in a discussion of illegal
activity. According to the affidavit, undercover agents had
less success speaking to Antonio and had only been able to
engage in “minimal contact such as greetings” with him.

   To justify the lack of attempts to infiltrate higher-level jobs
within GST, including those at the Blake Avenue office,
Hill’s affidavit stated that GST immediately filled every high-
level job with people “closely connected to the Gonzalez fam-
  1
   The appellees made a motion before this court to supplement the
record with evidence that this infiltration was decidedly aimed at a Los
Angeles bus terminal, and not at the Blake Avenue office. This motion
was denied.
7434            UNITED STATES v. GONZALEZ, INC.
ily.” The evidence produced in the Franks hearing, however,
indicated that only one of the 25 people with offices at Blake
Avenue was a member of the Gonzalez family and at least
some high-ranking officials were hired after responding to
newspaper advertisements, suggesting that undercover work
could be fruitful.

   The affidavit in support of the Blake Avenue wiretap also
stated that “several current and ex-employees of [GST] rang-
ing from dispatchers to managers have been interviewed” and
“provided valuable historical information” about GST. None
of these CIs, however, was identified as having worked at the
Blake Avenue office. Furthermore, the affidavit makes no
claim that federal agents ever tried to recruit CIs from the
Blake Avenue office before seeking the wiretap.

   Finally, Agent Hill’s affidavit dismissed as impractical a
handful of investigative techniques that had not been tried
before the Blake Avenue wiretap was sought. The affidavit
stated that trash runs were not utilized because the office trash
bin was inside a fence. Although Agent Hill’s affidavit stated
that “many of [GST’s] records may be held in [GST’s] head-
quarters,” the affidavit rejected the use of a search warrant at
the Blake Avenue office because such a search might “not
result in the discovery of sufficient evidence to show the
responsibility of Corporate officers and employees such as
Francisco and Antonio Gonzales.” At either location, the affi-
davit stated that use of search warrants or grand jury subpoe-
nas would reveal the investigation to the targets. The affidavit
also rejected the use of grand jury subpoenas on the belief that
conspirators would likely avail themselves of their Fifth
Amendment privilege against self-incrimination. On June 16,
2001, the Blake Avenue wiretap was terminated.

   Both Antonio and Francisco Gonzalez worked in the GST
headquarters on Blake Avenue and Antonio had an office in
the building. Antonio and Francisco jointly owned the Blake
Avenue building, but had leased the building to Gonzalez,
               UNITED STATES v. GONZALEZ, INC.           7435
Inc., dba GST, for a four-year term, which ended on May 31,
2001. The lease allowed a month-to-month continuance after
the four-year term ended. On July 31, 2002, Antonio and
Francisco terminated the lease.

   On August 15, 2003, Gonzalez, Inc. along with 10 individ-
ual defendants, including Antonio and Francisco, filed a joint
motion to suppress all evidence resulting from the Terminal
wiretap, its extension, and the Blake Avenue wiretap. Defen-
dants alleged that the wiretap applications contained material
misrepresentations and omissions and, therefore, violated
Title III of the Omnibus Crime Control and Safe Streets Act
of 1968, as amended, 18 U.S.C. §§ 2510-2522. The defen-
dants requested, and were granted, a Franks hearing to deter-
mine whether the affidavits submitted in support of the
wiretap applications contained intentional or reckless mis-
statements or omissions of material fact regarding the neces-
sity for the wiretaps.

   On November 25, 2003, the district court granted in part
and denied in part the defendants’ motion to suppress the
wiretap evidence. The court found that the Terminal wiretap
and its 30-day extension were authorized, but concluded that
the government had not met its burden of proving necessity
for the Blake Avenue wiretap, and therefore, that any evi-
dence from that wiretap must be suppressed. The district court
did not explicitly find that there were any material misstate-
ments or omissions in any of the wiretap affidavits that
negated the necessity for the wiretap orders.

   On December 19, 2003, the district court found that Anto-
nio and Francisco Gonzalez had standing to challenge all
intercepted communications from the Blake Avenue wiretap.
The government timely appeals the suppression of evidence
from the Blake Avenue wiretap and the granting of standing
to Antonio and Francisco to challenge all intercepted calls
under the Blake Avenue wiretap.
7436           UNITED STATES v. GONZALEZ, INC.
                        DISCUSSION

   [1] When Congress enacted the wiretapping provisions of
the Omnibus Crime Control and Safe Streets Act, 18 U.S.C.
§§ 2510-2522, it intended to “make doubly sure that the statu-
tory authority [for wiretaps] be used with restraint and only
where the circumstances warrant the surreptitious interception
of wire and oral communications.” United States v. Giordano,
416 U.S. 505, 515 (1974). Narrow construction of the
wiretapping provisions furthers Congress’ dual purposes for
the act of “ ‘(1) protecting the privacy of wire and oral com-
munications, and (2) delineating on a uniform basis the cir-
cumstances and conditions under which the interception of
wire and oral communications may be authorized.’ ” Gelbard
v. United States, 408 U.S. 41, 48 (1972) (quoting S. Rep. No.
90-1097, at 66 (1968), reprinted in 1968 U.S.C.C.A.N. 2122,
2153).

   [2] To enforce the privacy-centered purposes of these pro-
visions, Congress created important statutory prerequisites for
obtaining wiretap orders, including the requirement that the
government must prove necessity before it may utilize the
unconventional method of wiretaps as an investigative tool.
Congress also granted standing for any aggrieved person to
move to suppress any evidence from a wiretap unlawfully
employed. Finally, the Supreme Court, in Franks, created a
route to invalidate wiretap orders if the affidavits supporting
them conceal or misrepresent material facts leading a judge
inappropriately to find necessity for a wiretap order. 438 U.S.
154.

   While the district court below did not find material misrep-
resentations or omissions in the preparation of the affidavit,
it concluded that the evidence presented within the four cor-
ners of the affidavit failed to establish the necessity for the
Blake Avenue wiretap. Accordingly, the district court ordered
that the evidence produced from this wiretap must be sup-
pressed.
                UNITED STATES v. GONZALEZ, INC.            7437
I. The Defendants Made the Requisite Showing to
Warrant a Franks Hearing

   The government argues that the district court erred in grant-
ing a hearing pursuant to Franks to determine whether the
applications for the Terminal and Blake Avenue wiretaps con-
tained material misrepresentations or omissions. We disagree.
This court reviews de novo a district court’s decision to grant
a Franks hearing, but reviews the court’s factual determina-
tion concerning misleading statements and omissions after
such a hearing under the clearly erroneous standard. United
States v. Shryock, 342 F.3d 948, 975 (9th Cir. 2003), cert.
denied, 541 U.S. 965 (2004); United States v. Tham, 960 F.2d
1391, 1395 (9th Cir. 1992); United States v. Ippolito, 774
F.2d 1482, 1484 (9th Cir. 1985).

   To obtain a Franks hearing, defendants must make a pre-
liminary showing that the wiretap applications contained
material misrepresentations or omissions. Shryock, 342 F.3d
at 977; United States v. Bennett, 219 F.3d 1117, 1124 (9th
Cir. 2000). The defense filed 100 pages of attachments to sup-
port its claims of misrepresentations and omissions in the
wiretap affidavits. These documents made a sufficient offer of
proof to support defendants’ claims that the affidavits (1) mis-
represented the limited use of pole cameras in this investiga-
tion; (2) misrepresented that further physical surveillance was
highly likely to be compromised; (3) inaccurately portrayed
the government’s CIs as having less access to GST’s key offi-
cers than they actually possessed; and (4) misrepresented the
ability of the government to place an undercover agent in the
Blake Avenue office.

  [3] The district court correctly determined that the defense
adequately pled that the misrepresentations and omissions
were made with the requisite state of mind. Our case law does
not require clear proof of deliberate or reckless omissions or
misrepresentations at the pleading stage. United States v. Sta-
nert, 762 F.2d 775, 781 (9th Cir. 1985). Instead, at this stage
7438            UNITED STATES v. GONZALEZ, INC.
we simply require the defense to make a substantial showing
that supports a finding of intent or recklessness. Id. Given the
affiant’s key role in the investigation, we can conclude that he
knew or should have known the veracity of the challenged
statements in his affidavit because these statements all con-
cerned the potential of traditional investigative techniques to
gather information on the role any individuals at the Blake
Avenue office played in the alleged conspiracy.

   [4] The defendants also adequately pled materiality. Each
of the alleged misrepresentations and omissions related to the
ability of customary investigative tools to produce the evi-
dence sought by the government in its investigation into the
Blake Avenue office. Therefore, any finding of a material
misrepresentation or omission would undermine the govern-
ment’s ability to prove the need for the Blake Avenue wire-
tap. Because the defendants made an adequate initial showing
of intentional or reckless material misrepresentations or omis-
sions in the wiretap application, the district court did not err
in holding a Franks hearing. It is of no matter that the district
court ultimately decided, after an evidentiary hearing, that no
Franks violation occurred. This is, after all, the purpose of a
hearing.

   On appeal, the defendants urge us to conclude that the dis-
trict court implicitly found a Franks violation with respect to
the Blake Avenue wiretap application. According to the
defendants, because the district court ultimately concluded
that the affidavit in support of the Blake Avenue wiretap
failed to establish necessity, the court implicitly found that the
affidavit contained material misrepresentations or omissions
in violation of Franks. The defendants speculate that the dis-
trict court did not make this finding explicit out of a desire not
to malign the agent who wrote the affidavit. Although this is
a possible interpretation of the district court order, we are not
in the business of putting words in the mouth of the district
court to uncover a district court’s phantom finding. Therefore,
we will not graft an implicit finding of a Franks violation
                UNITED STATES v. GONZALEZ, INC.            7439
onto the district court’s order. As an appellate court, our duty
to evaluate all supportable bases for affirming a district court
finding is triggered only when the finding itself has been
explicitly made.

II.   Necessity for the Blake Avenue Wiretap was not
      Established

   The government urges us to reverse the district court’s
determination that the application in support of the Blake
Avenue wiretap failed to establish necessity. We review de
novo whether a full and complete statement of the facts sup-
porting a wiretap application was submitted in compliance
with 18 U.S.C. § 2518(1)(c). United States v. Canales Gomez,
358 F.3d 1221, 1224 (9th Cir. 2004); United States v.
McGuire, 307 F.3d 1192, 1197 (9th Cir. 2002). Such review
includes an assessment of whether the affidavit attests that
adequate investigative tactics were exhausted before the wire-
tap order was sought or that such methods reasonably
appeared unlikely to succeed or too dangerous. United States
v. Lynch, 367 F.3d 1148, 1159 (9th Cir. 2004). However, we
review the issuing court’s ultimate decision to authorize a
wiretap for an abuse of discretion. Canales Gomez, 358 F.3d
at 1225; McGuire, 307 F.3d at 1197.

   In support of its argument regarding the district court’s
necessity finding, the government points to portions of the
district court’s order indicating that the court may have con-
sidered evidence produced in the Franks hearing to reach its
necessity conclusion. Only the evidence presented within the
four corners of the wiretap application can be used to evaluate
necessity. 18 U.S.C. § 2518(3)(c). We hold that based solely
on the statements in the affidavit, it was error for the issuing
judge to conclude that the government had met its burden of
establishing necessity for the Blake Avenue wiretap and thus
affirm the district court’s decision.

   [5] To obtain a wiretap, the government must overcome the
statutory presumption against this intrusive investigative
7440            UNITED STATES v. GONZALEZ, INC.
method by proving necessity. United States v. Blackmon, 273
F.3d 1204, 1207 (9th Cir. 2001); Ippolito, 774 F.2d at 1486
(citing Giordano, 416 U.S. at 515; United States v. Bailey,
607 F.2d 237, 241 n.11 (9th Cir. 1979)). Together, 18 U.S.C.
§ 2518(1)(c) and (3)(c) comprise the necessity requirement
for wiretap orders. According to 18 U.S.C. § 2518(1)(c), the
government may establish necessity for a wiretap by any of
three, alternative methods. The government may show that
traditional investigative procedures (1) have been tried and
failed; (2) reasonably appear unlikely to succeed if tried; or
(3) are too dangerous to try. See also United States v. Smith,
31 F.3d 1294, 1298 n.2 (4th Cir. 1994).

   This circuit has interpreted these necessity provisions to
require a “full and complete statement of specific allegations”
establishing the necessity of the wiretap sought. Blackmon,
273 F.3d at 1207 (citing Ippolito, 774 F.2d at 1486). When
reviewing necessity we employ a “common sense approach”
to evaluate the reasonableness of the government’s good faith
efforts to use traditional investigative tactics or its decision to
forego such tactics based on the unlikelihood of their success
or the probable risk of danger involved with their use. Black-
mon, 273 F.3d at 1207; United States v. Commito, 918 F.2d
95, 98 (9th Cir. 1990).

  A. Normal investigative procedures had not been
  adequately utilized

   The district court below concluded that the government did
not appropriately utilize traditional investigative methods
before requesting the Blake Avenue wiretap. The district
court found that before the order was sought “[n]o indepen-
dent verification of any significance was really done to indi-
cate why the wiretaps at the Blake Office were necessary.”
We agree. Read in the most generous light, the Hill affidavit
submitted in support of the Blake Avenue wiretap contended
that only the following investigative methods targeted at the
Blake Avenue office were tried before a wiretap was sought:
                UNITED STATES v. GONZALEZ, INC.              7441
(1) five-days-worth of pen register analysis; (2) an equally
short use of trap-and-trace analysis; and (3) limited physical
surveillance of the Blake Avenue office. As discussed below,
this limited use of traditional methods does not establish that
normal tools were sufficiently exhausted before the govern-
ment requested a wiretap.

   First, the affidavit revealed that for five days the govern-
ment used pen registers, which recorded calls dialed from the
target telephones at the Blake Avenue office, and trap-and-
trace devices, which recorded the incoming calls to these tele-
phones. As these devices simply record numbers dialed or
received, they are inherently unlikely to reveal the kind of
information the government was seeking on the scope of the
conspiracy. We have held that the use of pen registers alone
is insufficient to establish necessity for a wiretap. Carneiro,
861 F.2d at 1183 n.16. In addition, this court has also refused
to condone a wiretap order when the supporting application
only established that law enforcement pursued traditional
investigative methods that were unlikely to produce pertinent
evidence before seeking the wiretap. Id. at 1183.

   Second, the Hill affidavit indicated that limited physical
surveillance of the Blake Avenue office was tried, but aban-
doned because agents “were unable to detect any activities
consistent with the evidence previously gathered in the inves-
tigation because of the layout of the building and its location
near a residential neighborhood.” The affidavit also stated that
agents were once “followed by a vehicle in what may have
been a counter surveillance effort.” In Blackmon, this court
rejected the notion that a single incident of failed physical sur-
veillance could establish that any subsequent surveillance
could be ruled out as likely to be unsuccessful or too danger-
ous to pursue. 273 F.3d at 1209.

  Third, Agent Hill averred that prior to the Blake Avenue
wiretap application one attempt was made to infiltrate “one of
[GST’s] Los Angeles offices,” but the affidavit does not indi-
7442            UNITED STATES v. GONZALEZ, INC.
cate whether this infiltration attempt was focused, like every
other infiltration discussed, on a bus terminal or if the attempt
was targeted at the Blake Avenue office itself. The description
of this attempt in the affidavit, as being targeted to “one of the
Los Angeles offices” as opposed to “the Los Angeles office”
or even the “Blake Avenue office” made it impossible for the
issuing judge to conclude that this infiltration attempt was
focused on the Blake Avenue office.

   In its affidavit, the government also argues that the limited
information produced by the Terminal wiretap linking Anto-
nio and Francisco to the alleged conspiracy justify the Blake
Avenue wiretap. The fact that traditional investigatory tactics
directed at GST’s Arizona activities — or even the extraordi-
nary measure of wiretapping phones in Arizona bus terminals
— did not produce sufficient evidence linking GST employ-
ees working out of the Los Angeles office on Blake Avenue
to the alleged conspiracy is hardly surprising. Nor is such a
claim adequate evidence that traditional investigative tools
were exhausted with respect to the newer, Los Angeles-
targeted stage of the investigation. Only the failure of “nor-
mal,” not extraordinary, investigative measures justifies the
statutory necessity requirement.

   [6] Even when all of the traditional investigative techniques
reportedly used in conjunction with the investigation into the
Blake Avenue office are viewed together, it is clear that the
steps taken before the Blake wiretap was sought fall short of
what our case law requires. Cf. Carneiro, 861 F.2d at 1178
(upholding wiretap order where the DEA used CIs, surveil-
lance, pen registers, and undercover agents before resorting to
a wiretap). In reaching our holding, we are cognizant that the
necessity requirement should not be interpreted to require law
enforcement to exhaust every possible technique before
resorting to wiretapping, but to ensure that in the usual case
wiretapping is not used as the first meaningful step in an
investigation. Carneiro, 861 F.2d at 1181; United States v.
Brone, 792 F.2d 1504, 1506 (9th Cir. 1986); United States v.
                UNITED STATES v. GONZALEZ, INC.              7443
Martin, 599 F.2d 880, 887 (9th Cir. 1979); see also Ippolito,
774 F.2d at 1486. In our judgment, the facts attested to in the
Hill affidavit indicate that the government side-stepped its
responsibility to use promising traditional techniques when it
began to investigate the Blake Avenue office, and instead
conducted only the most cursory investigation before seeking
a wiretap. We hold that the necessity provisions require the
government to do more.

  B. Unutilized investigative procedures were reasonably
  likely to succeed

  [7] Even though the government failed to show that it had
used an ample array of traditional investigative tools before
seeking the Blake Avenue wiretap, the government would
have proven necessity had it reasonably attested that the
unused tools were unlikely to succeed. Ippolito, 774 F.2d at
1486. The government has made no such showing. On the
contrary, the wiretap application itself showed that law
enforcement did not first attempt, without success, traditional
investigative methods that may have been “potentially pro-
ductive.” Id.

    First, although the affidavit claimed that neither physical
nor video surveillance was likely to produce useful informa-
tion as the Blake Avenue “headquarters are housed in a build-
ing that has large darkened windows that do not allow either
physical or video visual surveillance of the activities inside,”
we cannot accept this as evidence that such surveillance was
reasonably unlikely to bear fruit. Surely surveillance is not
completely unsuccessful if it does not decipher what an indi-
vidual is writing while she sits at her desk. Accepting the lim-
itations of the location of the office as noted in the affidavit,
it is still reasonable to conclude that video or physical surveil-
lance could have identified individuals, such as known coy-
otes (those who assist in the illegal entry of persons for a fee),
coming and going from the Blake Avenue office. This infor-
mation certainly would have assisted law enforcement in dis-
7444            UNITED STATES v. GONZALEZ, INC.
covering the identities of “members of the criminal enterprise
and aiders and abettors,” a stated purpose of the Blake Ave-
nue wiretap.

   Second, the facts presented in the Blake Avenue affidavit
suggest that the use of confidential informants or undercover
agents in relation to the Blake Avenue was a potentially pro-
ductive, but unutilized tool. These methods not only have the
potential to provide highly detailed information on those
working at the Blake office, but also as the affidavit itself
indicated, these tools had already proven effective in earlier
stages of the investigation. The Hill affidavit discusses the
useful information obtained from CIs during the earlier stages
of the investigation targeted at the bus terminals, but the affi-
davit makes no claims that CIs were ever recruited from the
Blake Avenue office. This information should have led the
issuing judge to question why the government did not attempt
to use CIs to investigate the Blake Avenue office.

   Third, the affidavit’s terse rejection of the possible produc-
tive use of grand jury subpoenas or search warrants does not
establish that these investigative techniques were reasonably
unlikely to work. The affidavit rejects these tools by claiming
they would likely reveal the investigation to its targets. Such
statements do not reasonably explain why traditional investi-
gative tools are unlikely to succeed in a particular investiga-
tion, but are “boilerplate conclusions that merely describe
inherent limitations of normal investigative procedures,”
which we have found insufficient to establish necessity.
Blackmon, 273 F.3d at 1210; see also id. at 1211 (The fact
“that traditional investigation methods do not reveal all are
generic problems of police investigation. Their generic nature
does not dissipate simply because the government claims a
vast investigative purpose. . . . The government may not cast
its investigative net so far and so wide as to manufacture
necessity in all circumstances.”)

  [8] To cover its failure to establish necessity for the Blake
Avenue wiretap, the Hill affidavit attempted to shoe-horn the
               UNITED STATES v. GONZALEZ, INC.             7445
significant investigatory work the government conducted
before applying for the Terminal wiretap into its application
for the Blake Avenue wiretap. But the government is not free
to transfer a statutory showing of necessity from one applica-
tion to another — even within the same investigation. This
court has held that an issuing judge may not examine various
wiretap applications together when deciding whether a new
application meets the statutory necessity requirement. Each
wiretap application must separately satisfy the necessity
requirement. See Carneiro, 861 F.2d at 1180-81 (upholding
an initial wiretap order, but invalidating subsequent orders
covering other suspects because the later applications did not
show that particularized investigative actions were targeted,
without success, at each later suspect); see also Brone, 792
F.2d at 1507. Accordingly, we hold that the Blake Avenue
wiretap application did not establish that adequate traditional
tools were tried before the wiretap was sought or that these
untried alternatives were reasonably unlikely to be productive.

  C. Unused investigative       procedures    were   not    too
  dangerous to be tried

   [9] The affidavit in support of the Blake Avenue wiretap
makes no claim that normal investigative procedures were
reasonably determined to be too dangerous to try. Quite sensi-
bly, the necessity requirement for a wiretap order does not
compel law enforcement officers to use traditional investiga-
tive strategies at the risk of danger to themselves or others.
See McGuire, 307 F.3d at 1197 (upholding a wiretap order
without requiring exhaustion of traditional investigative tools
due to the “grave dangers” involved with any such effort
because of the target “group’s known violent propensity and
undisputed possession of assault weapons”). The Blake Ave-
nue affidavit contained no statements supporting a finding
that law enforcement had any reason to fear danger from any-
one associated with the office.

  [10] A district court’s decision to grant a motion to sup-
press wiretap evidence is reviewed de novo. United States v.
7446           UNITED STATES v. GONZALEZ, INC.
Reyna, 218 F.3d 1108, 1110 (9th Cir. 2000). But the court’s
underlying factual findings are reviewed under the clearly
erroneous standard. United States v. Bynum, 362 F.3d 574,
578 (9th Cir. 2004). The court below correctly determined
that the affidavit in support of the Blake Avenue wiretaps
failed to meet the statutory necessity requirements. Based
solely on the evidence presented in the affidavit, it was evi-
dent that the government made limited use of traditional, and
potentially productive, investigative methods before seeking
the Blake Avenue wiretap. The affidavit did not allege suffi-
ciently that these strategies were reasonably unlikely to suc-
ceed or too dangerous to try. Therefore, the issuing court
abused its discretion in concluding that the government estab-
lished necessity for the Blake Avenue wiretap. Because this
wiretap did not meet the statutory necessity requirements, the
evidence obtained from it is “fruit of the poisonous tree,” and
must be suppressed. 18 U.S.C. § 2515 (codifying the fruit of
the poisonous tree doctrine for wiretapping evidence).

III. Antonio and Francisco have Standing to Challenge
the Conversations Intercepted under the Blake Avenue
Wiretap

   The government also appeals the district court’s order
granting Antonio and Francisco Gonzalez standing to chal-
lenge the contents of all conversations intercepted by the
Blake Avenue wiretap, not simply those conversations in
which they participated. The question of whether a particular
defendant has standing to challenge the legality of a search is
a mixed question of law and fact. We review the district
court’s ultimate legal conclusion on standing de novo, and the
findings of fact related to this conclusion for clear error.
United States v. Sarkisian, 197 F.3d 966, 986 (9th Cir. 1999).

   [11] For the purposes of challenging wiretaps, the relevant
statute provides that

    Any aggrieved person in any trial . . . before any
    court . . . of the United States . . . may move to sup-
               UNITED STATES v. GONZALEZ, INC.               7447
    press the contents of any wire or oral communication
    intercepted pursuant to this chapter, or evidence
    derived therefrom, on the grounds that . . . the order
    of authorization or approval under which it was
    intercepted is insufficient on its face.

18 U.S.C. § 2518(10)(a). The statute defines an aggrieved
person as one “who was a party to any intercepted wire, oral,
or electronic communication or a person against whom the
interception was directed.” 18 U.S.C. § 2510(11) (emphasis
added). The Supreme Court has interpreted these provisions
as limiting standing to challenge wiretaps to persons whose
Fourth Amendment rights were violated by the interception.
Alderman v. United States, 394 U.S. 165, 175-76, n.9 (1969);
see also United States v. King, 478 F.2d 494, 506 (9th Cir.
1973). The touchstone for Fourth Amendment standing analy-
sis is whether the individual asserting her right to challenge
the interception had a reasonable expectation of privacy in the
place where the wiretap was used. See, e.g., O’Connor v.
Ortega, 480 U.S. 709, 711-12 (1987). We hold that the dis-
trict court correctly determined that Antonio and Francisco
Gonzalez had such a reasonable expectation of privacy at the
Blake Avenue office that they owned and in which they had
substantial control of the day-to-day operations.

   [12] The Supreme Court has held that owners of the prem-
ises where an illegal wiretap occurs have standing to chal-
lenge the interception, even if the owners did not participate
in the intercepted conversations. Alderman, 394 U.S. at 175-
76; see also King, 478 F.2d at 506 (“[A] defendant may move
to suppress the fruits of a wire-tap only if his privacy was
actually invaded; that is, if he was a participant in an inter-
cepted conversation, or if such conversation occurred on his
premises.”) (emphasis added). Although the government con-
cedes that the Gonzalezes owned the Blake Avenue property,
it suggests that Alderman and King are distinguishable
because the premises at issue in those cases were residential,
not commercial properties, and because it is well-established
7448            UNITED STATES v. GONZALEZ, INC.
that an individual’s expectation of privacy is lower in a com-
mercial property. See, e.g, New York v. Burger, 482 U.S. 691,
700 (1987). At least in the instant case, we do not find this to
be a distinction that makes a difference.

   [13] In determining whether the Gonzalezes had a reason-
able expectation of privacy over the intercepted calls, it is
important to assess the nature of the location where these con-
versations were seized. See O’Connor, 480 U.S. at 715 (1987)
(“[T]he reasonableness of an expectation of privacy . . . is
understood to differ according to context . . . .” ) The Blake
Avenue office was a small, family-run business housing only
25 employees at its peak. In such an office, individuals who
own and manage the business operation have a reasonable
expectation of privacy over the on-site business conversations
between their agents. In reaching this result, we do not rule
out the possibility that the hands-off executives of a major
corporate conglomerate might lack standing to challenge all
intercepted conversations at a commercial property that they
owned, but rarely visited. Instead, we simply hold that
because the Gonzalezes were corporate officers and directors
who not only had ownership of the Blake Office but also
exercised full access to the building as well as managerial
control over its day-to-day operations, they had a reasonable
expectation of privacy over calls made on the premises.

                        CONCLUSION

   In conclusion, we affirm the district court’s determination
that defendants made a showing sufficient to require a Franks
hearing, however, we decline to find an implicit Franks viola-
tion by the district court with respect to any of the wiretap
applications. In addition, we affirm the district court’s finding
that the government failed to prove the necessity for the Blake
Avenue wiretap. Thus, we also affirm the district court’s
order suppressing any evidence resulting from this wiretap.
Lastly, we uphold the district court’s determination that Anto-
               UNITED STATES v. GONZALEZ, INC.          7449
nio and Francisco Gonzalez have standing to challenge all the
calls intercepted pursuant to the Blake Avenue wiretap.

  AFFIRMED.
