WASHINGTON (AP) — A lawyer who aided former President Donald Trump’s efforts to undo the 2020 election results said in a federal court filing Monday that federal agents seized his cell phone last week.

John Eastman said the agents took his phone as he left a restaurant last Wednesday evening, the same day federal law enforcement officials conducted similar activity around the country as part of broadening investigations into efforts by Trump allies to overturn the election results. Eastman said the agents who approached him appeared to be serving a warrant from the Justice Department’s Office of Inspector General.

The action was disclosed in a filing in federal court in New Mexico in which Eastman challenges the legitimacy of the warrant, calling it overly broad, and asks that a court force the federal government to return his phone. The filing does not specify where exactly agents seized his phone, and a lawyer for Eastman did not immediately return an email seeking comment.

Federal agents last week served a raft of subpoenas related to a scheme by Trump allies to put forward alternate, or fake, slates of electors in hopes of invalidating the election won by Democrat Joe Biden.

Also Wednesday, agents searched the Virginia home of Jeffrey Clark, a Trump Justice Department official who encouraged Trump’s challenges of the election results.

A spokeswoman for the inspector general declined to comment.

Eastman has been a central figure in the ongoing hearings by the House committee investigating the Jan. 6, 2021, assault on the U.S. Capitol, though he has not been among the witnesses to testify.