– A secretive letter shared with senators and federal investigators by the senior Democrat on the Senate Judiciary Committee charges that a teenage Brett Kavanaugh and a male friend trapped a teenage girl in a bedroom during a party and tried to assault her, according to three people familiar with the contents of the letter.

The letter says that Kavanaugh, then a student at Georgetown Preparatory School in suburban Washington and now President Donald Trump's Supreme Court nominee, had been drinking at a social gathering when he and the male friend took the teenage girl into a bedroom. The door was locked, and she was thrown on the bed. Kavanaugh then got on top of the teenager and put a hand over her mouth as the music was turned up, according to the account.

But the young woman was able to extricate herself and leave the room before anything else occurred, the letter says.

The woman says she considered the incident an assault. She has declined to be publicly identified, and she asked Sen. Dianne Feinstein of California, the top Democrat on the Judiciary Committee, not to publicize the letter.

In a statement shared by the White House, Kavanaugh said the charges were false.

"I categorically and unequivocally deny this allegation," he said. "I did not do this back in high school or at any time."

The alleged episode took place more than 30 years ago, when all three individuals involved were minors. The New York Times has not seen the letter, but its contents were described by the three people.

With speculation about the letter's contents circulating this week, Sen. Chuck Grassley, R-Iowa, chairman of the Judiciary Committee, released a different letter Friday, sent to him and to Feinstein and signed by 65 women who say they knew Kavanaugh while in high school.

"Through the more than 35 years we have known him, Brett has stood out for his friendship, character, and integrity," the women wrote. "In particular, he has always treated women with decency and respect. That was true when he was in high school, and it has remained true to this day."

Grassley was still planning to move ahead with Kavanaugh's confirmation. The Judiciary Committee is scheduled to hold a key vote to advance the nomination Thursday, and Republican leaders hope to hold a final vote of the full Senate before the end of September to allow Kavanaugh to be seated before the start of the Supreme Court's fall term next month. Grassley's aides said Kavanaugh had been the subject of six FBI background checks since 1993, and none had turned up anything like the episode in question.

It was not immediately clear how, if at all, the accusation would influence senators who must decide whether to give Kavanaugh a lifetime appointment to the court. Only a small group of moderate senators remain publicly undecided about their votes, and objections from either one of two undecided Republicans, Sens. Susan Collins of Maine and Lisa Murkowski of Alaska, could thwart confirmation.

Collins spent an hour on the phone with Kavanaugh on Friday, shortly after details of the letter were first published. The call had been scheduled for days, and neither the White House nor Collins' office would discuss what was said.

The White House and outside pro-Kavanaugh groups continued to accuse Democrats of playing dirty, withholding mysterious information until the eve of Kavanaugh's confirmation in a last-ditch effort to derail a nominee they have always opposed.

"The claims are wholly unverifiable and come at the tail-end of a process that was already marred by ugly innuendo, dishonesty, and the nastiest form of our politics," Sen. Orrin Hatch, R-Utah, said Friday. "The American people deserve much better from the Senate as an institution."

Tom Mentzer, a spokesman for Feinstein, released a statement Friday afternoon saying, "Senator Feinstein was given information about Judge Kavanaugh through a third party. The senator took these allegations seriously and believed they should be public. However, the woman in question made it clear she did not want this information to be public. It is critical in matters of sexual misconduct to protect the identity of the victim when they wish to remain anonymous, and the senator did so in this case."