A former F.B.I. lawyer intends to plead guilty after he was charged with falsifying a document as part of a deal with prosecutors conducting their own criminal inquiry of the Russia investigation, according his lawyer and court documents made public on Friday.

The lawyer, Kevin Clinesmith, 38, who was assigned to the Russia investigation, plans to admit that he altered an email from the C.I.A. that investigators relied on to seek renewed court permission in 2017 for a secret wiretap on the former Trump campaign adviser Carter Page, who had at times provided information to the spy agency. Mr. Clinesmith’s lawyer said he made a mistake while trying to clarify facts for a colleague.

The plea deal, first reported by The New York Times, could be unveiled in court later Friday, the sources said.

Clinesmith’s lawyer issued a statement to The Washington Post apologizing for his conduct.

“Kevin deeply regrets having altered the email. It was never his intent to mislead the court or his colleagues as he believed the information he relayed was accurate. But Kevin understands what he did was wrong and accepts responsibility,” the lawyer told the Post.

Clinesmith’s misconduct was first revealed last December in a Justice Department inspector general report that widely criticized the FBI’s conduct in the Russia collusion probe against President Trump. The report said he worked in the FBI general counsel’s office and altered an email to hide the fact that former Trump campaign adviser Carter Page was a source for the CIA.