FOR PUBLICATION

UNITED STATES COURT OF APPEALS

FOR THE NINTH CIRCUIT

UNITED STATES OF AMERICA,

Plaintiff-Appellee,

v.

SHANE MAURITZ 

VANDERGROEN,

Defendant-Appellant.

No. 19-10075

D.C. No.

4:18-cr-00133-PJH-1

OPINION

Appeal from the United States District Court

for the Northern District of California

Phyllis J. Hamilton, Chief District Judge, Presiding

Argued and Submitted May 13, 2020

San Francisco, California

Filed July 7, 2020

Before: Michelle T. Friedland and Mark J. Bennett, Circuit 

Judges, and Jed S. Rakoff,* District Judge. 

Opinion by Judge Rakoff

* The Honorable Jed S. Rakoff, Senior District Judge for the 

Southern District of New York, sitting by designation.
2 UNITED STATES V. VANDERGROEN

SUMMARY**

Criminal Law

The panel affirmed the district court’s denial of a motion 

to suppress evidence found during a search that followed a 

911 call and the stop of the defendant’s car, in a case in 

which the defendant was convicted of being a felon in 

possession of a firearm.

The panel held that the 911 call generated reasonable 

suspicion justifying the stop, where the identified caller 

using an emergency line was reliable, the reports by three 

other persons conveyed by the caller contained sufficient 

indicia of reliability, and the reported activity—possessing a 

concealed weapon—was presumptively unlawful in 

California and ongoing.

The panel addressed other issues in a concurrently filed 

memorandum disposition.

COUNSEL

Jerome E. Matthews (argued) and Robin Packel, Assistant 

Federal Public Defenders; Steven G. Kalar, Federal Public 

Defender; Office of the Federal Public Defender, Oakland, 

California; for Defendant-Appellant.

** This summary constitutes no part of the opinion of the court. It 

has been prepared by court staff for the convenience of the reader.
UNITED STATES V. VANDERGROEN 3

Alexis J. Loeb (argued), Assistant United States Attorney; 

Merry Jean Chan, Chief, Appellate Section; David L. 

Anderson, United States Attorney; United States Attorney’s 

Office, San Francisco, California; for Plaintiff-Appellee.

OPINION

RAKOFF, District Judge:

Late on a Saturday evening, a worker at a bar in 

California called 911 to report that three patrons had seen a 

man in the area with a pistol on him. In response to this call, 

the police stopped the man as he drove away, discovered a 

pistol in his car, and placed him under arrest. The man, 

defendant-appellant Shane Vandergroen, was subsequently 

convicted of being a felon in possession of a firearm in 

violation of 18 U.S.C. § 922(g)(1). Vandergroen now argues 

that the 911 call should never have led to his stop in the first 

place because it did not generate reasonable suspicion, and 

that the evidence of the pistol should therefore have been 

excluded. We disagree, and affirm the district court’s denial 

of Vandergroen’s motion to suppress.1

I. Factual Background

At about 11:27 p.m. on February 17, 2018, an individual 

(“Witness 2”) who worked at a bar called Nica Lounge 

1 In a concurrently filed memorandum disposition, we reject

Vandergroen’s alternative suppression arguments, as well as his

challenge to his conviction based on Rehaif v. United States, 139 S.Ct. 

2191 (2019).
4 UNITED STATES V. VANDERGROEN

(“Nica”) in Concord, California called 9112 to report a man 

with a gun seen on his person. Witness 2 gave his name, 

identified his position at Nica, and indicated he was calling 

from the bar. He explained that three of Nica’s customers 

had told him they saw a man in the area with a pistol “on 

him.” Witness 2 said the man (whom he could see) was in 

the back parking lot and had just walked into a neighboring 

bar. Witness 2 described the man as “Latin,” “wearing a blue 

sweater with a Warriors . . . logo,” “skinny,” and in his early 

20s, features that mostly matched Vandergroen’s.3

Continuing in the call, Witness 2 next reported that the 

man had walked out of the neighboring bar and was in the 

parking lot next to Nica Lounge. The operator asked for 

more details about the man, including whether the suspect 

had been fighting. Witness 2 said the man had not. The 

operator also asked Witness 2 where the gun was located on 

the defendant, and the witness indicated that he would ask 

the patrons who reported the gun to him. Before Witness 2 

could provide more information, however, the man started 

running through the parking lot by Nica. Witness 2 started 

reporting the man’s movements, including that the man 

jumped into a black four-door sedan. Witness 2 identified 

the car as a “Crown Vic,” noted the man was driving out of 

the parking lot, and told police officers arriving on the scene 

2 The Government’s brief appears to assume that the call was 

directly to police dispatch rather than to 911. Although the difference is 

immaterial to our decision, the basis for the Government’s assumption is 

unclear. Given that the district court characterized the call as a 911 call, 

and the record does not indicate this finding was clearly erroneous, we 

adopt this characterization. See United States v. Torres, 828 F.3d 1113, 

1118 (9th Cir. 2016) (“We review the denial of a motion to suppress 

evidence de novo, and any underlying factual findings for clear error.”).

3 Vandergroen is not, however, Latino.
UNITED STATES V. VANDERGROEN 5

which car to follow. At the end of the call (“the 911 call”), 

Witness 2 provided his full name and phone number.

In response to the 911 call, dispatch alerted officers that 

“patrons think they saw a HMA [Hispanic Male Adult] 

blu[e] warriors logo carrying a pistol.” Dispatch directed 

officers to “1907 Salvio[,] Nica Lounge,” and stated,

3 patrons think they saw an HMA with a blue 

sweatshirt on carrying a pistol. We’re getting 

further. . . . HMA wearing a blue sweatshirt 

with a Warriors logo on it. . . currently IFO 

Pizza Guys. . . . no 4-15 [i.e. no fight] prior to 

patrons seeing the male with a pistol. 

3 females say they saw it on him. We’re still 

getting further. . . . Subject is running4

toward DV8 Tattoos and just got into a black 

vehicle. . . getting into a 4-door sedan, black 

in color . . .

Shortly thereafter, an officer reported over the dispatch 

“we’re gonna do a high-risk car stop.” The police then 

executed a stop of the man, later identified as Vandergroen. 

During this stop, the police conducted a search of 

Vandergroen’s car and found a loaded semi-automatic 

handgun under the center console to the right of the driver’s 

seat. An officer then placed Vandergroen under arrest.

Vandergroen was subsequently charged in a single-count 

indictment with being a felon in possession of a firearm, in 

violation of 18 U.S.C. § 922(g)(1). Before trial, 

Vandergroen filed a motion to suppress evidence found in 

4 Vandergroen started running before the police arrived on the scene, 

and there is no indication that he did so in response to the police.
6 UNITED STATES V. VANDERGROEN

the course of his arrest, arguing, inter alia, that the 911 call 

did not generate reasonable suspicion justifying his initial 

stop. The district court denied the motion. Vandergroen then 

requested that the case be set for a stipulated-facts bench 

trial, reserving the right to appeal the denial of the motion to 

suppress. After accepting the parties’ factual stipulations, the 

district court adjudged Vandergroen guilty. Vandergroen 

filed a timely notice of appeal.

II. Standard of Review

We review the denial of a motion to suppress de novo, 

and any underlying findings of fact for clear error. United 

States v. Torres, 828 F.3d 1113, 1118 (9th Cir. 2016).

III. Analysis

On appeal, Vandergroen argues that evidence discovered 

in the course of his arrest should be suppressed because the 

police did not have reasonable suspicion to stop him in the 

first instance. Under the Fourth Amendment, an officer may 

conduct a brief investigative stop only where she has “a 

particularized and objective basis for suspecting the 

particular person stopped of criminal activity,” commonly 

referred to as “reasonable suspicion.” Navarette v. 

California, 572 U.S. 393, 396–97 (2014) (citations omitted). 

While a tip such as the 911 call may generate reasonable 

suspicion, it can only do so when, under the “totality-of-thecircumstances,” it possesses two features. United States v. 

Rowland, 464 F.3d 899, 907 (9th Cir. 2006) (citation 

omitted). First, the tip must exhibit sufficient indicia of 

reliability, and second, it must provide information on 

potential illegal activity serious enough to justify a stop. 

United States v. Edwards, 761 F.3d 977, 983 (9th Cir. 2014). 

The 911 call here satisfied both requirements.
UNITED STATES V. VANDERGROEN 7

A. Reliability

The Supreme Court and this circuit have identified a 

number of factors that can demonstrate the reliability of a 

tip, including whether the tipper is known, rather than 

anonymous, Florida v. J.L., 529 U.S. 266, 270 (2000); 

whether the tipper reveals the basis of his knowledge, 

Rowland, 464 F.3d at 908; whether the tipper provides 

detailed predictive information indicating insider 

knowledge, id.; whether the caller uses a 911 number rather 

than a non-emergency tip line, Foster v. City of Indio, 

908 F.3d 1204, 1214 (9th Cir. 2018); and whether the tipster 

relays fresh, eyewitness knowledge, rather than stale, 

second-hand knowledge, United States v. Terry-Crespo, 

356 F.3d 1170, 1176–77 (9th Cir. 2004). When evaluating 

the reliability of a tip such as the 911 call here, in which a 

caller reports information from a third party regarding 

possible criminal activity, we consider the reliability of both 

the caller himself and the third party whose tip he conveys. 

See United States v. Brown, 925 F.3d 1150, 1153 (9th Cir. 

2019) (considering both the fact that the caller was known 

and that the third-party tipster was anonymous in evaluating 

the reliability of such a tip).

The totality of the circumstances in this case 

demonstrates that the 911 call was sufficiently reliable to 

support reasonable suspicion. First, the statements by 

Witness 2 himself were undoubtedly reliable. Witness 2 

provided his name and employment position, making him a 

known, and therefore more reliable, witness. See J.L., 

529 U.S. at 270 (noting that a known informant is more 

reliable); see also Rowland, 464 F.3d at 907 (“[A] known 

informant’s tip is thought to be more reliable . . . .”). Further, 

Witness 2 “reveal[ed] the basis of [his] knowledge”—

explaining that multiple patrons told him that Vandergroen 
8 UNITED STATES V. VANDERGROEN

had a gun on him and offering to ask follow-up questions to 

the patrons about the exact location of the gun—thereby 

enhancing the tip’s reliability. Rowland, 464 F.3d at 908. 

Finally, the fact that Witness 2 placed his call using an 

emergency line, which allows calls to be recorded and 

traced, increased his credibility. Foster, 908 F.3d at 1214.

Second, we conclude that, viewed collectively, the 

statements by Nica’s patrons were also reliable. Although 

the patrons remained anonymous during the call,5 which 

generally cuts against reliability, their statements 

“exhibit[ed] ‘sufficient indicia of reliability’” to overcome 

this shortcoming. J.L., 529 U.S. at 270 (quoting Alabama v. 

White, 496 U.S. 325, 327 (1990)). The reports were based on 

fresh, first-hand knowledge. The patrons reported personally 

seeing the gun on Vandergroen shortly before they reported 

it to Witness 2. “[P]olice may ascribe greater reliability to a 

tip, even an anonymous one, where an informant was 

reporting what he had observed moments ago, not stale or 

second-hand information.” Terry-Crespo, 356 F.3d at 1177 

(internal quotation marks and citation omitted). 

Furthermore, the fact that the anonymous tipsters were 

Nica’s patrons who were still at the bar when the 911 call 

was being made “narrowed the likely class of informants,” 

making their reports more reliable. Id. at 1174. Further still, 

the fact that multiple individuals reported seeing a gun also 

made the information more reliable. The existence of 

multiple tipsters, though anonymous, mitigates the specter 

of “an unknown, unaccountable informant . . . seeking to 

5 That the FBI was later able to identify one of the witnesses for an 

interview, does not alter this analysis. “The reasonableness of official 

suspicion must be measured by what the officers knew before they 

conducted their search,” not after. Florida v. J.L., 529 U.S. 266, 271 

(2000).
UNITED STATES V. VANDERGROEN 9

harass another [by] set[ting] in motion an intrusive, 

embarrassing police search” by relaying false information. 

J.L., 529 U.S. at 271–72. Taken together, these factors 

rendered the information provided by the Nica’s patrons 

through Witness 2 sufficiently reliable to support reasonable 

suspicion.

United States v. Brown, 925 F.3d 1150 (9th Cir. 2019), 

contrary to Vandergroen’s contention, does not suggest 

otherwise. In Brown, we determined that a call made by an 

identified witness at the behest of an anonymous witness 

reporting a man with a gun did not support reasonable 

suspicion because the tip was neither reliable nor indicative 

of potentially illegal activity. As we explained, “[t]he tip 

suffer[ed] from two key infirmities—an unknown, 

anonymous tipster and the absence of any presumptively 

unlawful activity.” Id. at 1153. Brown does not control in 

this case because the 911 call here was both more reliable 

than the tip in Brown and (as explained further below) 

conveyed information about presumptively unlawful 

conduct.

As to reliability, whereas the tip in Brown originated 

from a single witness who made clear “that she did not want 

to provide a firsthand report because she ‘[does not] like the 

police,’” id. at 1152 (alteration in original), the 911 call here 

conveyed information from three witnesses, and none of 

them expressed reluctance to be held directly accountable for 

their reports. Moreover, the caller who relayed the tip in 

Brown did not personally see the suspect. Id. By contrast, the 

Nica employee in this case was looking at Vandergroen 

while making the 911 call, and was able to help the police 

identify Vandergroen by describing his movements in realtime. This factor further bolstered the reliability of the tip. 

Cf. Foster, 908 F.3d at 1214 (“One factor supporting the 
10 UNITED STATES V. VANDERGROEN

reliability of a tip is that the tipster claims eyewitness 

knowledge, coupled with sufficient detail in his 

description.”).

B. Potential Illegality of Reported Behavior

While the 911 call was thus reliable, it may only support 

reasonable suspicion if it also “provide[d] information on 

potential illegal activity.” Foster, 908 F.3d at 1214. In other 

words, a tip must demonstrate that “criminal activity may be 

afoot,” id. (quoting Terry v. Ohio, 392 U.S. 1, 30 (1968)), 

and the “absence of any presumptively unlawful activity” 

from a tip will render it inadequate to support reasonable 

suspicion, Brown, 925 F.3d at 1153. Furthermore, any 

potential criminal activity identified must be serious enough 

to justify “immediate detention of a suspect.” United States 

v. Grigg, 498 F.3d 1070, 1080–81 (9th Cir. 2007).

The 911 call gave the police reason to suspect 

Vandergroen was carrying a concealed firearm, which is 

presumptively a crime in California. See Cal. Penal Code 

§ 25400. Witness 2 indicated that patrons had seen 

Vandergroen with a gun “on him.” This language, conveyed 

to the police by the dispatcher, would suggest to a reasonable 

police officer that Vandergroen at least potentially had the 

gun concealed on his body. We have recognized that because 

California “makes it generally unlawful to carry a concealed 

weapon without a permit . . . a reasonable officer could 

conclude that there is a high probability that a person 

identified in a 911 call as carrying a concealed handgun is 

violating California’s gun laws.” Foster, 908 F.3d at 1215–

16. As such, the tip provided information on potentially 

illegal activity. This was in contrast to the tip in Brown, 

which did not describe conduct that was presumptively 

illegal in Washington, where that case arose. See id.; cf. 

Brown, 925 F.3d at 1153–54 (holding that a tip that a man in 
UNITED STATES V. VANDERGROEN 11

Washington was carrying a gun was not “reliable in its 

assertion of illegality” because “[i]n Washington State, it is 

presumptively lawful to carry a gun”).

Furthermore, the potentially illegal activity identified in 

the 911 call was serious enough to justify the “immediate 

detention of [the] suspect.” Grigg, 498 F.3d at 1080. In some 

circumstances, a tip that a suspect has completed only a 

misdemeanor may not support reasonable suspicion absent a 

“likelihood for ‘ongoing or repeated danger,’ or 

‘escalation.’” Johnson v. Bay Area Rapid Transit Dist., 

724 F.3d 1159, 1175 (9th Cir. 2013) (quoting Grigg, 

498 F.3d at 1081) (holding that a stop for a reported 

completed misdemeanor battery was not justified where the 

suspect was “doing nothing but talking” when the officer 

arrived). Vandergroen argues that his conduct was too minor 

to justify a stop because it consisted at most of a completed 

“wobbler,” that is a crime that is punishable as either a felony 

or misdemeanor. Vandergroen fails to note, however, that 

the police had reason to suspect he was committing an 

ongoing crime when stopped in his car because the crime of 

carrying a concealed weapon includes concealing the 

weapon in a car. Cal. Penal Code § 25400(a)(1). The tip’s 

indication that Vandergroen was engaging in this continuing 

illegal activity means that there was an ongoing danger and 

the immediate detention of Vandergroen was warranted.

IV. Conclusion

In short, the 911 call in this case was both reliable and 

provided information on potentially criminal behavior. 

Witness 2 was reliable as an identified caller using an 

emergency line, and the Nica patrons’ reports he conveyed 

contained sufficient indicia of reliability to support 

reasonable suspicion. Furthermore, the reported activity—

possessing a concealed weapon—was presumptively 
12 UNITED STATES V. VANDERGROEN

unlawful in California and was ongoing at the time of the 

stop. Thus, the 911 call generated reasonable suspicion 

justifying the stop and the district court was correct to deny 

Vandergroen’s motion to suppress the evidence obtained 

during the stop.

AFFIRMED.