Avenatti made the announcement on Twitter Wednesday morning, naming his client as Julie Swetnick. In the tweet, he described her as courageous, brave and honest.
Here is a picture of my client Julie Swetnick. She is courageous, brave and honest. We ask that her privacy and that of her family be respected. pic.twitter.com/auuSeHm5s0— Michael Avenatti (@MichaelAvenatti) September 26, 2018
Below is my correspondence to Mr. Davis of moments ago, together with a sworn declaration from my client. We demand an immediate FBI investigation into the allegations. Under no circumstances should Brett Kavanaugh be confirmed absent a full and complete investigation. pic.twitter.com/QHbHBbbfbE— Michael Avenatti (@MichaelAvenatti) September 26, 2018
The attorney also tweeted images of what he said was a sworn statement from his client, adding, "Under no circumstances should Brett Kavanaugh be confirmed absent a full and complete investigation."
In the three-page declaration, Swetnick said she witnessed Kavanaugh "consistently engage in excessive drinking and inappropriate contact of a sexual nature with women in the early 1980s."
Avenatti also provided the declaration to the Senate Judiciary Committee, which is reviewing it. It includes an allegation that she was raped at a party in 1982 by multiple boys while she was incapacitated and unable to consent.
Swetnick does not identify the alleged perpetrators or the location but claims that the party was attended by Kavanaugh. She does not contend that Kavanaugh was among her alleged assailants.
Kavanaugh released a statement denying the new charges.
"This is ridiculous and from the Twilight Zone," he said. "I don't know who this is and this never happened."
RELATED: Here's what each accuser says about Brett Kavanaugh
President Trump also reacted Wednesday to the new allegations, taking direct aim at Avenatti, a vocal critic of the president and a potential challenger to Trump in 2020.
"Avenatti is a third rate lawyer who is good at making false accusations like he did on me and like he is now doing on Judge Brett Kavanaugh," the president tweeted. "He is just looking for attention and doesn't want people to look at his past record and relationships - a total low-life!"
Two other women have come forward with allegations of sexual misconduct against Kavanaugh.
California professor Christine Blasey Ford has accused Kavanaugh of sexually assaulting her at a high school party, while Deborah Ramirez said in a story published Sunday by The New Yorker Magazine that Kavanaugh placed his penis in front of her and caused her to involuntarily touch it during a drunken dormitory party.
Kavanaugh denies all three accusations.
Related: Brett Kavanugh accuser's lawyers submit 4 affidavits backing up assault story
The Associated Press contributed to this report.
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