San Francisco conviction overturned: Warrantless detention is not supported by collective knowledge of police.


Defendant was convicted in the Superior Court, San Francisco County, of domestic battery, and he appealed from denial of his motion to suppress evidence.

The Superior Court, Appellate Division, held the State could not rely on “collective knowledge” doctrine to justify the defendant’s warrantless detention. The trial court failure to suppress evidence discovered during an unconstitutional, warrantless stop of defendant was not harmless beyond a reasonable doubt. The conviction was reversed.


Domestic violence complaint and no identification by victim

San Francisco Police Department Officer Philip Leung investigated a report of domestic violence at Macy’s. Leung met Amyah S., who claimed that her ex-boyfriend hit her earlier that day. Amyah described her ex-boyfriend as a “mid-Eastern male, 6’ tall, about 150 in weight, wearing a gray Nike jumpsuit and black slip-ons.” Leung broadcasted the description and dispatch also provided “a rough basic description.” Leung’s sergeant notified him that “they found a possible suspect” and Leung drove Amyah to the suspect, Arshia Chalak, near Union Square. Chalak was handcuffed and surrounded by several police officers. Amyah, sitting in the front passenger seat of Leung’s patrol vehicle, said that the man was not the one who hit her.

The officers did not release Chalak, but took his phone. Not believing Amyah was being truthful about her identification, Leung asked Amyah to call her ex-boyfriend and she called twice. An officer heard Chalak’s phone ring twice. An unknown officer took Chalak to a police station for further investigation. Leung drove Amyah back to Macy’s, and she told him that Chalak was the man who hit her.

Chalak was charged by misdemeanor complaint with domestic battery (Pen. Code, § 243, subd. (e)(1); count 1). On October 25, 2018, appellant filed a motion to suppress evidence. On November 21, 2018, the trial court denied the motion. On December 3, 2018, a jury convicted appellant of count 1. Chalak filed an appeal.

The trial court erred when it denied appellant’s motion to suppress evidence.

A motion to suppress evidence may be made on the ground that “[t]he search or seizure was unreasonable.” (Pen. Code, § 1538, subd. (a)(1)(A).) A search or seizure without a warrant is presumed to be unreasonable The prosecution bears the burden of proving a legal justification for the search or seizure. (People v. Williams (1999) 20 Cal.4th 119, 127, 83 Cal.Rptr.2d 275, 973 P.2d 52.) the Fourth Amendment requires that an officer “point to specific articulable facts that, considered in light of the totality of the circumstances” that objectively show that the person detained may be involved in criminal activity.” (People v. Souza (1994) 9 Cal.4th 224, 231, 36 Cal.Rptr.2d 569, 885 P.2d 982.)

Here the detaining officer’s identity is not know and she did not testify at the suppression hearing. Nothing in the record establishes that the detaining officer had any information linking the person in the description to a crime or possessed specific articulable facts demonstrating that Chalak may have been involved in criminal activity.

The collective knowledge doctrine:

The People argued that they need only present evidence that there was reasonable suspicion to detain, not that any particular officers had reasonable suspicion. They assert that Leung’s reasonable suspicion can be imputed to the detaining officer through the collective knowledge doctrine.

The collective knowledge doctrine looks to the collective knowledge of all officers involved in the investigation even though not all of the information obtained by the investigating officers may have been communicated to the officer who detains or arrests the suspect.(United States v. Ramirez (9th Cir. 2007) 473 F.3d 1026, 1032.)

“[A] detaining officer who is not personally aware of all the facts on which a reasonable suspicion might be based may nevertheless properly detain an individual on the basis of a direction or information transmitted by police officers who were personally aware of such facts.” (People v. Soun (1995) 34 Cal.App.4th 1499, 1521, 40 Cal.Rptr.2d 822; see United States v. Shareef (10th Cir. 1996) 100 F.3d 1491, 1503 [“The cases in which we have applied the ‘collective knowledge’ rule all have involved actual communication to the arresting officer of either facts or a conclusion constituting probable cause, or an arrest order.”]

Collective knowledge doctrine not applicable where police detain without information about criminal activity

The prosecution failed to establish that the detaining officer had any information about domestic violence was suspected. There was no evidence that Leung conveyed to the detaining officer that he had a reasonable suspicion or probable cause to believe that the person described was involved in criminal activity.

A legal detention because of ‘suspicious circumstances,’ requires specific and articulable facts, which reasonably caused the officer to believe that (1) some activity out of the ordinary had taken place or was occurring or about to occur; (2) the activity was related to crime; and (3) the individual under suspicion was connected to the activity. [Citation.]” (People v. Bower (1979) 24 Cal.3d 638, 644, 156 Cal.Rptr. 856, 597 P.2d 115.)

Here, the circumstances of the detention are unknown, and the prosecution failed to establish that the detaining officer was provided with reasonable suspicion of a crime. Therefore, the prosecution did not meet its burden of proof in justifying the detention. The trial court should have granted the motion to suppress.

The prosecution has not established that the error was harmless beyond a reasonable doubt.

“[B]efore a federal constitutional error can be held harmless, the court must be able to declare a belief that it was harmless beyond a reasonable doubt” and did not contribute to the verdict. (Chapman v. California (1967) 386 U.S. 18, 24, 87 S.Ct. 824, 17 L.Ed.2d 705.) Here, a substantial portion of the investigation linking Chalak to the assault of Amyah occurred as a result of his unlawful detention. Amyah did not initially identify appellant as the person who assaulted her. Identification of Chalak using his cell phone took place well after the unlawful detention. The violation of Chalak’s Fourth Amendment right to be secure against unreasonable seizures was not harmless beyond a reasonable doubt.

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