Brown and other attorneys general filed an amicus brief Monday in the U.S. Court of Appeals for the D.C. Circuit. The brief supports a lawsuit challenging the Department of Homeland Security’s policies and practices for making civil immigration arrests without warrants.

Federal law allows immigration officers to make such an arrest without a warrant only when they have probable cause to believe a person is unlawfully present in the United States and likely to flee before a warrant can be obtained. The attorneys general contend officers routinely make arrests without assessing whether someone poses that risk.

Brown said constitutional protections against unlawful searches and seizures must apply to federal enforcement, and called checks and balances essential to fair policing.

The brief describes effects the coalition says immigration enforcement has had in Washington: students missing school, agricultural work being disrupted, and people avoiding medical care or losing access to courts, libraries and grocery stores. It also says enforcement has strained family finances and weakened trust between immigrant communities and local law enforcement.

The attorneys general further argue that agents’ use of masks, plainclothes and unmarked vehicles, as well as failures to identify themselves, has intensified fear and uncertainty during operations.

Brown was joined by attorneys general from other states and the District of Columbia, including Oregon and California. The filing asks the federal appeals court to consider the states’ arguments as it reviews the challenge to the arrest practices.