The Senate Judiciary Committee asked the FBI on Saturday to investigate a man who made an unfounded rape claim against Supreme Court nominee Judge Brett M. Kavanaugh and then later recanted, saying the man had acted in bad faith.

Chairman Charles E. Grassley said the committee had to waste resources tracking down the claim by the man, who said Judge Kavanaugh raped one of his friends back in the 1980s. The man said he and another friend went to beat Judge Kavanaugh up — then said he recognized him recently when television showed Judge Kavanaugh after he was nominated to the high court.

Mr. Grassley didn’t name the man, but after reporters tracked him down, he recanted.

“Such acts are not only unfair; they are potentially illegal. It is illegal to make materially false, fictitious or fraudulent statements to congressional investigators. It is illegal to obstruct committee investigations,” Mr. Grassley wrote in a letter to Attorney General Jeff Sessions and FBI Director Christopher A. Wray.

The move to demand an FBI probe could deter others from coming forward with false allegations over the upcoming days, while Judge Kavanaugh’s nomination remains in limbo.

The FBI is currently investigating other allegations against Judge Kavanaugh, including a sexual assault claim made by Christine Blasey Ford, who in powerful testimony told senators on Thursday of being assaulted by Judge Kavanaugh at a high school party in 1982. She said she most remembered him and his friend, Mark Judge, laughing at her as they assaulted her.

Judge Kavanaugh indignantly refuted her claim to senators, saying that while he didn’t question she was assaulted, it wasn’t him.

Several others have also come forward, including a woman who says the judge exposed himself to her during an alcohol-fueled party at Yale University, and another woman who has made a shocking and convoluted allegation that the judge was complicit in gang rapes of high school girls.

Judge Kavanaugh has vehemently refuted those, too.

But they seemed to unleash ludicrousness, with one man from Rhode Island complaining to Sen. Sheldon Whitehouse, Rhode Island Democrat, about an alleged rape committed by the judge on a boat in the 1980s. The man said after learning of the rape, he and a friend went to the boat and beat up the judge and an accomplice.

The bizarre story had no support.