8/24/26: reasonable suspicion and post-trial acceptance of responsibility

In United States v. Aguilera, --- F.4th ---, No. 25-3366 (9th Cir. 2026), the Court affirmed Fernando Aguilera’s conviction following a bench trial for being a felon in possession of ammunition under 18 U.S.C. § 922(g)(1), vacated his sentence, and remanded for resentencing.

This case arises from a police encounter following reports of an active shooter in San Francisco’s Mission District. Defendant-Appellant Fernando Aguilera was convicted of being a felon in possession of ammunition under 18 U.S.C. § 922(g)(1). His appeal raises two issues. First, Aguilera appeals the district court’s denial of his motion to suppress the ammunition evidence, asserting officers did not have reasonable suspicion to conduct a warrantless seizure of his person. Second, Aguilera appeals his sentence, arguing the district court erred by denying him an offense level reduction for acceptance of responsibility and relying on impermissible sentencing factors. 

Under the Fourth Amendment, law enforcement officers must have reasonable suspicion to conduct an investigatory stop of an individual. United States v. Brignoni-Ponce, 422 U.S. 873, 878 (1975). “Reasonable suspicion is defined as ‘a particularized and objective basis for suspecting the particular person stopped of criminal activity.’” United States v. Cotterman, 709 F.3d 952, 968 (9th Cir. 2013) (en banc) (quoting United States v. Cortez, 449 U.S. 411, 417– 18 (1981)). Courts measure reasonable suspicion “by what the officers knew before they conducted their search [or seizure],” Florida v. J.L., 529 U.S. 266, 271 (2000), and assess the totality of the circumstances, rather than certain factors in isolation, see United States v. Valdes-Vega, 738 F.3d 1074, 1078–79 (9th Cir. 2013) (en banc) (citing United States v. Arvizu, 534 U.S. 266, 273–74 (2002)). Reasonable suspicion requires more than a hunch, but “considerably less than proof of wrongdoing by a preponderance of the evidence.”

The district court properly found Aguilera’s seizure was supported by reasonable suspicion. The court considered the collective knowledge of the officers, see United States v. Ramirez, 473 F.3d 1026, 1032 (9th Cir. 2007), and the totality of the circumstances, in concluding the officers reasonably suspected that Aguilera was the shooter who fired a gun outside El Trebol. Eyewitnesses identified the shooter to the responding officers, and Officer Hurtado visually identified a person matching the suspect’s description, location, and direction of travel. At one point, Officer Hurtado was as little as five feet from the suspect.

In light of the totality of the circumstances described above and the officers’ collective belief that the suspect had a loaded firearm, it is clear the officers had reasonable suspicion to detain the individual hiding behind a white fence in a manner that did not jeopardize their safety. See Wardlow, 528 U.S. at 124–25 (citing Cortez, 449 U.S. at 418) (“[T]he determination of reasonable suspicion must be based on commonsense judgments and inferences about human behavior.”). Contrary to what Aguilera suggests, Officer Frisk had a clear view of Aguilera’s clothing through “a large gap in the fence, and pointed his flashlight directly at defendant before detaining him,” and therefore, he would have been able to see if Aguilera matched the eyewitness descriptions. Thus, we agree with the district court’s findings that officers possessed adequate reasonable suspicion to detain Aguilera

Aguilera argues his sentence should be vacated because the district court applied the wrong legal standard and relied on impermissible factors in denying the acceptance of responsibility reduction. . . .“Whether or not the defendant has accepted responsibility . . . is a factual finding that we review for clear error.” Id. Because we conclude the district court applied the wrong legal standard, we remand for resentencing. 

“When a defendant’s ‘statements and conduct make it clear that his contrition is sincere, he is entitled to the reduction.’” United States v. Green, 940 F.3d 1038, 1042 (9th Cir. 2019) (cleaned up) (quoting United States v. Cortes, 299 F.3d 1030, 1038 (9th Cir. 2002)). Although “there can be a fine line between putting on a defense at trial, and expressing contrition at sentencing,” this determination “is not a binary, ‘either/or’ proposition.”

Like the decision to go to trial or a constitutional challenge to a criminal statute, a motion to suppress evidence under the Fourth Amendment “is an assertion of a constitutional right.” United States v. Vance, 62 F.3d 1152, 1157 (9th Cir. 1995). In Vance, the panel noted that a district court erred by “holding it against [the defendant] that he moved to suppress evidence before pleading guilty.” Id. We have repeatedly emphasized that “a sentencing court cannot consider against a defendant any constitutionally protected conduct.” Hernandez, 894 F.3d at 1109 (citation omitted) (emphasis in original). Indeed, “a judge cannot rely upon the fact that a defendant refuses to plead guilty and insists on his right to trial as the basis for denying an acceptance of responsibility adjustment.” 

In the full context of the proceedings, it is apparent that the district court misapprehended the law regarding the acceptance of responsibility reduction and held Aguilera’s constitutionally protected conduct against him.

It is apparent from the record that the district court believed either that a defendant must unconditionally plead guilty to be eligible for the reduction, or that it could consider Aguilera’s constitutional motions and decision to go to trial against him. As discussed above, this reflects a misapprehension of the relevant legal standard.

“To establish harmlessness, the Government must show that ‘it is more probable than not’ that the error did not affect the sentence.” “When a defendant is sentenced under an incorrect Guidelines range—whether or not the defendant’s ultimate sentence falls within the correct range—the error itself can, and most often will, be sufficient to show a reasonable probability of a different outcome absent the error.”

Here, the district court acknowledged what the Guidelines range would have been with the reduction, 41 to 51 months, and without it, 51 to 63 months, but analyzed only the 51- to 63-month range. The court considered the standard sentencing factors and imposed a below-range sentence of 45 months. Because the district court did not conduct a separate analysis of the alternative Guidelines range, it did not satisfy the requirements for harmless error.

A court “must explain . . . the reason for the extent of a variance” which “necessarily is different when the range is different.” Id. Contrary to our dissenting colleague’s position, a district court’s mere acknowledgment of an alternative Guidelines range or “mere statement that it would impose the same above-Guidelines sentence no matter what the calculation” is not sufficient to establish harmless error. Id. Additionally, the probation office’s recommended sentence, 41 months, was at the low end of the lower range. Thus, a reasonable probability exists that the court may have imposed a lower sentence had it started from the 41 to 51-month range.