Who is Mark Judge? Brett Kavanaugh's high school friend and the only named witness Brett Kavanaugh's former classmate is a key figure in his confirmation process.

Brett Kavanaugh's high school classmate Mark Judge has become a pivotal yet enigmatic figure in the contentious confirmation hearings for the Supreme Court nominee.

Christine Blasey Ford, who testified under oath before the committee on Capitol Hill Thursday, alleges that Judge witnessed Kavanaugh sexually assault her at a party in suburban Maryland when they were teens in the early 1980s.

She told senators Thursday that the "uproarious laughter between the two," referring to Judge and Kavanaugh, was among the most painful memories of the alleged attack.

Kavanaugh and Judge have repeatedly denied the claims. Judge, who said he and Kavanaugh were "friends in high school," said in a statement he "never saw Brett act in the manner Dr. Ford describes."

In a letter to the Senate Judiciary Committee leadership on Friday, Judge said he will cooperate with any confidential law enforcement investigation into the accusations.

The only named witness

Ford, a 51-year-old psychology professor at Palo Alto University and a research psychologist at Stanford University in California, broke her silence after 36 years, telling senators she didn't speak of the alleged incident in detail to anyone until 2012 when she was in a couples therapy session with her husband.

She said she originally wanted to remain anonymous when she contacted her congressional representative in July, after learning that Kavanaugh was on President Donald Trump's shortlist of potential Supreme Court nominees. But once her accusations became public, Ford said she believed it was her "civic duty" to share her story.

After calling the office of her congresswoman, Ford said she also messaged The Washington Post's confidential tip line and identified Kavanaugh as her alleged assailant and Judge as a witness. Ford later agreed to speak publicly to a journalist at the newspaper and Judge was named in a Sept. 16 article about the alleged incident.

The Washington Post reported at the time that Judge declined to comment.

Two days prior to that article, before Ford's name was known, Judge gave an interview to The Weekly Standard in which he called the accusations "just absolutely nuts." He said The New Yorker had contacted him for comment on the allegations and that's when he first learned he was named in the woman's letter to lawmakers about Kavanaugh.

Judge's attorney, Barbara "Biz" Van Gelder, subsequently emailed a letter dated Sept. 18 to Sens. Chuck Grassley and Dianne Feinstein, the chairman and the ranking member of the Senate Judiciary Committee, respectively. The letter contained a statement from Judge, saying he has "no memory of this alleged incident" that Ford describes.

"Brett Kavanaugh and I were friends in high school but I do not recall the party described in Dr. Ford's letter. More to the point, I never saw Brett act in the manner Dr. Ford describes," Judge's statement reads, in part. "I have no more information to offer the Committee and I do not wish to speak publicly regarding the incidents described in Dr. Ford's letter."

'Wasted' high school years

Judge and Kavanaugh both attended Georgetown Preparatory School, an elite, all-boys Catholic high school in North Bethesda, Maryland, just outside Washington, D.C.

In 1997, Judge published a memoir about alcoholism during his teenage years, titled "Wasted: Tales of a Gen X Drunk," in which he recounts booze-soaked parties with his prep school friends and alcohol-fueled attempts to hook up with girls. He also recalls working "at the local supermarket" in the summer of 1982.

Judge has authored several other books and is now a Washington-based conservative writer whose byline has appeared in publications such as The Daily Caller and The American Spectator.

In a recent letter to the Senate Judiciary Committee leadership, Judge revealed he is a "recovering alcoholic and a cancer survivor" who has "struggled with depression and anxiety," and thus avoids public speaking.

Another accuser names Mark Judge

Since Ford's allegations became public, at least two other women have come forward accusing Kavanaugh of sexual misconduct and one of them also named Judge.

Michael Avenatti, an attorney who is known for representing adult film star Stormy Daniels, posted to Twitter Wednesday a photo of his newest client, Julie Swetnick of Washington, D.C., along with court documents detailing new allegations about the behavior of Kavanaugh and Judge during their high school years.

In a sworn declaration provided to the Senate Judiciary Committee, Swetnick alleges she "became aware of efforts" by Kavanaugh and Judge and others to spike girls' drinks at house parties.

Swetnick's declaration also includes an allegation that she was raped by multiple boys at a party in 1982 while she was incapacitated without her consent. She does not identify her alleged assailants or the location of the alleged incident but claims that Kavanaugh and Judge were "present."

Judge's attorney, Van Gelder, told ABC News in a statement Wednesday that her client "vehemently denies" the claims.

In a letter emailed to committee leadership Friday afternoon, Judge wrote that he doesn't know Swetnick and her allegations "are so bizarre that, even while suffering from my addiction, I would remember actions so outlandish."

'Uproarious laughter between the two'

During her testimony before the Senate Judiciary Committee on Thursday, a visibly distraught Ford recounted how the alleged assault occurred. She said she was attending a "small gathering" at a house in the Bethesda area one summer night in 1982. She claimed Kavanaugh and Judge were among the party-goers.

Ford said people at the party were drinking beer and she had one. She later went upstairs to use the restroom and was shoved from behind into a bedroom across from the bathroom, she said. She couldn't see who pushed her, she said, but Kavanaugh and Judge allegedly entered the room and locked the door behind them.

Ford said someone pushed her onto the bed and Kavanaugh allegedly got on top of her, "groped" her and tried to remove her clothes, while Judge allegedly alternated between egging him on and telling him to stop.

"I tried to yell for help. When I did, Brett put his hands over my mouth to stop me from yelling," she said. "Both Brett and Mark were drunkenly laughing during the attack. They seemed to be having a very good time. Mark seemed ambivalent, at times urging Brett on, at times telling him to stop. A couple of times, I made eye contact with Mark and thought he might try to help me. But he did not."

Seared into her memory is "the uproarious laughter between the two and their having fun at my expense," Ford told senators.

During the alleged assault, Ford said Judge jumped up on the bed twice while Kavanaugh was on top of her, causing them to topple over the second time and allowing Ford to get away. She ran out of the room, down the stairs and out of the house, she said.

Ford said she has not knowingly seen Kavanaugh since that night, but she claimed she saw Judge about six to eight weeks later at a Safeway in the Potomac, Maryland. Judge seemed to be employed at the supermarket chain when they ran into each other and she said "hello" to him, according to Ford.

Judge's face turned "white" and he seemed "very uncomfortable in saying hello back," she said.

"We had previously been friendly at the times we saw each other over the previous two years," Ford told senators. "I wouldn't characterize him as not friendly. He was just nervous and not really wanting to speak with me. He looked a bit ill."

'Bart O'Kavanaugh'

A visibly emotional and irate Kavanaugh also testified under oath before the Senate Judiciary Committee on Thursday, during which he denied all allegations against him.

Kavanaugh told senators he "never did anything remotely resembling what Dr. Ford describes" and has never been in a room alone with Ford and Judge.

Senators grilled Kavanaugh about his behavior during high school and questioned him about the veracity of Judge's book, "Wasted," in which Judge references a "Bart O'Kavanaugh" who "puked in someone's car" and "passed out on his way back from a party."

When asked whether that character was a pseudonym for him, Kavanaugh told senators they would "have to ask" Judge.

"Mark Judge was a friend of ours in high school who developed a very serious drinking problem and addiction problem that lasted decades and was very difficult for him to escape from and ... then he had leukemia as well on top of it," Kavanaugh said. "As part of his therapy or part of his coming to grips with sobriety, he wrote a book. That is a fictionalized book and an account."

'How'd you find me?'

After listening to hours of impassioned testimonies from both Ford and Kavanaugh, Democratic senators continued their calls for an FBI investigation into the accusations and for key witnesses, like Judge, to be interviewed.

That evening, Judge emailed a letter to the committee leadership asserting his and Kavanaugh's innocence.

"I do not want to comment about these events publicly. As a recovering alcoholic and a cancer survivor, I have struggled with depression and anxiety. As a result, I avoid public speaking," Judge wrote, in part. "Brett Kavanaugh and I were friends in high school, but we have not spoken directly in several years. I do not recall the events described by Dr. Ford in her testimony before the US Senate Judiciary Committee today. I never saw Brett act in the manner Dr. Ford describes."

His attorney, Van Gelder, also issued a statement on behalf of her client: "Mr. Judge does not recall the events described by Dr. Ford in her testimony before the US Senate Judiciary Committee today. We have told the Committee that Mr. Judge does not want to comment about these events publicly. We also have said that he is willing to answer written questions, and he has. In addition, he is willing to participate in a confidential, fact-finding investigation. He will not respond to any media inquiries."

Van Gelder told ABC News in an email Saturday that she nor her client are commenting during the proceedings.

Judge's whereabouts were unknown for several days as his name appeared in news articles and on TV. But a reporter with The Washington Post spotted him on Monday in Bethany Beach, Delaware, where he apparently has been laying low at a friend's beachfront house.

Judge wouldn't talk to the reporter beyond asking, "How'd you find me?"

Mark Judge says he will 'cooperate' with probe 'confidentially'

The Senate Judiciary Committee reconvened on Capitol Hill on Friday to vote on advancing Kavanaugh's Supreme Court nomination to the full Senate floor. The Republican-led committee defeated a motion from Sen. Richard Blumenthal (D-Conn.) to subpoena Judge.

"I'd like to make a motion to subpoena Mark Judge as a witness before our committee," Blumenthal said. "Evidently, he has never been interviewed by the FBI, he has never been questioned by any member of our committee, he has never submitted a detailed account of what he knows."

Blumenthal also asked the committee chairman for more time to make a final appeal to halt the confirmation process, which Grassley granted.

The meeting resumed later that afternoon and Sen. Jeff Flake (R-Arizona) suggested delaying the Senate floor vote "for up to and not more than one week" to allow the FBI to conduct an investigation into any allegations against Kavanaugh. The committee subsequently voted 11-10, along party lines, to send the nomination to the floor.

Judge emailed a letter to the committee leadership, saying he will "with any law enforcement agency that is assigned to confidentially investigate these allegations."

Just as daylight began to wane from the skyline of the nation's capital, Trump announced he has ordered an FBI supplemental probe of Kavanaugh.

"I’ve ordered the FBI to conduct a supplemental investigation to update Judge Kavanaugh’s file," the president said in a statement Friday evening. "As the Senate has requested, this update must be limited in scope and completed in less than one week."