NEW YORK — A lawyer allied with Donald Trump is expected to testify Monday before a New York grand jury, giving the former president an indirect opportunity to make a case that he shouldn’t face criminal charges over hush money paid during his 2016 campaign.

Robert Costello was asked to appear by the Manhattan district attorney’s office after he said he had information raising questions about the credibility of Michael Cohen, a key witness in the investigation, according to a person familiar with the matter who insisted on anonymity to discuss secret legal proceedings.

His testimony will come two days after Trump said he expected to face criminal charges and urged supporters to protest his possible arrest. In a series of social media posts through the weekend, the Republican former president criticized the New York investigation, directing particularly hostile rhetoric toward Manhattan District Attorney Alvin Bragg, a Democrat.

It was unclear whether Costello’s testimony has any potential to change the course of a grand jury probe that seems close to concluding.

Costello briefly acted as a legal adviser to Cohen after the FBI raided Cohen’s home and apartment in 2018. At the time, Cohen was being investigated for both tax evasion and for payments he helped orchestrate in 2016 to buy the silence of two women who claimed to have had sexual encounters with Trump.

For several months, it was unclear whether Cohen, a longtime lawyer and fixer for the Trump Organization who once boasted that he would “take a bullet” for his boss, would remain loyal to the president.

Cohen ultimately decided to plead guilty in connection with the payments to porn actor Stormy Daniels and model Karen McDougal, which he said were directed by Trump. Since then, he has been a vociferous Trump critic, testifying before Congress and then to the Manhattan grand jury.

Trump, who has denied having sex with either woman, has castigated Cohen as a liar. Costello broke with Cohen before he pleaded guilty, after it became clear he was no longer in Trump’s camp.

In the years since, Costello, a veteran New York attorney, has represented Trump allies including his former political strategist Steve Bannon and his personal lawyer Rudy Giuliani.

The Manhattan district attorney’s office declined to comment on Sunday.