The attorneys for Michael Cohen, President Donald Trump’s longtime personal lawyer, are expected to stop representing him in the criminal investigation into his business dealings, according to a person familiar with the matter.

Mr. Cohen’s attorneys are reviewing more than 3.7 million documents federal prosecutors seized in an April raid of Mr. Cohen’s home, office and hotel room to designate which communications they see as protected by attorney-client privilege, ahead of a Friday deadline set by Judge Kimba Wood of the Southern District of New York.

Stephen Ryan, Todd Harrison and others at the firm McDermott, Will & Emery LLP, which has been representing Mr. Cohen since June 2017, will cease doing so after that review is complete, the person said.

Mr. Cohen doesn’t yet have a replacement law firm but is searching for a federal criminal lawyer in New York, people familiar with the matter said. Mr. Cohen wants to hire a lawyer with close ties to the Manhattan U.S. attorney’s office, the people said.

Mr. Cohen hasn’t yet decided whether he will cooperate with prosecutors in the case, according to one of those people. He hasn’t been charged with any crime.