Judge Curbs Warrantless Immigration Arrests Across Southern California

LOS ANGELES – A federal judge has barred immigration officers in Southern California from carrying out warrantless civil immigration arrests unless they first determine that the person is likely to flee.

In a preliminary injunction issued Sept. 2 and unsealed Wednesday, U.S. District Judge Maame Ewusi-Mensah Frimpong ruled that officers must weigh the “totality of the circumstances known to the agent or officer” when deciding whether someone is likely to escape before making an immigration arrest without a warrant.

The case was brought last fall by the American Civil Liberties Union of Southern California, Public Counsel and Los Angeles-area immigrant advocacy organizations amid an unprecedented increase in immigration enforcement across the region. The order covers the Central District of California, including Los Angeles, Orange, Riverside, San Bernardino, Ventura, Santa Barbara and San Luis Obispo counties.

Frimpong also directed the government to fully document the probable cause supporting an arrest before a warrant could be secured. Simply being in the United States illegally does not, by itself, justify a warrantless arrest, the judge wrote.

“Without this, Defendants cannot show that any arrest was proper,” Frimpong said in her order. She also rejected the government’s request to pause or postpone the injunction while it pursued an appeal.

The U.S. Department of Homeland Security did not immediately respond to a request for comment.

The lawsuit additionally sought to halt roving immigration patrols that conduct stops and arrests solely on the basis of race, language or occupation, while also safeguarding detained people’s access to legal counsel.

Frimpong had earlier imposed a temporary restraining order limiting those broad immigration enforcement operations. The U.S. Supreme Court lifted that restriction last September, with Justice Brett Kavanaugh writing that apparent ethnicity may be relevant to a stop when considered alongside other information.

The preliminary injunction concerning warrantless immigration arrests followed an Aug. 13 hearing, when Frimpong indicated in a tentative ruling that she was likely to rule for the plaintiffs.

Federal judges in Portland, Colorado, Washington, D.C., and the Eastern District of California have previously blocked similar warrantless immigration arrest practices.

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Plaintiffs argued in court documents that in many arrests they tracked in Southern California, no documentation was ever produced showing the arresting officers documented the likelihood of escape.

“There’s no statutory requirement to document,” said federal attorney Daniel Mummolo, adding that different arresting officers handle things differently.

He cited a memo issued in January 2026 by former acting director of U.S. Immigration and Customs Enforcement Todd Lyons that said officers could make an “on-the-spot” determination about likelihood of escape.

“You have not presented evidence of officers saying, ‘Yeah I didn’t write it down but I did do it,’ ” Frimpong said in response.

Plaintiffs’ attorney Laura Perry Stone said the memo requires officers to determine both that the person was likely to leave the location and is unlikely to be found at another identifiable location, such as their home or workplace.

In her order, Frimpong said that a “wealth of record evidence” including government directives, arrest narratives, agent depositions and video evidence showed the government’s current policy and practice was to conduct an escape risk assessment based solely on unlawful status or “false assertions,” or to not conduct one at all.

In one instance, the government claims that an individual was “running away” from immigration agents before being questioned. But a video of the arrest showed him walking at a normal pace and texting on his phone before the agent began questioning him, Frimpong wrote.

“This court order should put an end to hundreds – if not more – of unlawful arrests that continue throughout Southern California,” said Mayra Joachin, an attorney with the ACLU of Southern California. “We will closely monitor compliance with this court order, and expect the federal government to abide by it.”