A woman is suing the billionaire investor Leon Black, accusing him of raping her at Jeffrey Epstein's Manhattan townhouse when she was 16 years old.

The lawsuit describes in gruesome detail the woman's account of a sexual assault that left her bleeding and sobbing. Her lawyers say that the woman, identified as Jane Doe, has autism and a rare form of Down syndrome that has left her "developmentally... about 12 years old."

A lawyer for Black, Susan Estrich, said Black has never met the woman and called the lawsuit "frivolous" and full of "vicious and defamatory lies." Estrich also says the suit was "manufactured by the Wigdor law firm," which had filed a previous sexual assault complaint against Black that was eventually thrown out.

A spokesman for Black, Whit Clay, echoed Estrich's denial, saying the law firm "has an agenda" and that its credibility has been impugned by the dismissal of the previous suit.

In response to the vendetta claim, Jeanne M. Christensen, a partner at Wigdor, said that Black's "conspiracy theories and finger-pointing are an obvious attempt to shift the focus away from his heinous acts."

Black, who is 71, is the co-founder and former CEO of Apollo Global Management. He left the private equity firm in 2021, shortly after a New York Times report revealed that he allegedly regularly dined with Epstein and paid him for consulting and other services. An internal Apollo investigation that documented his $158 million payment to Epstein found no wrongdoing.

The latest suit is the third to publicly accuse Black of rape. He has denied all the allegations. In addition to the case that was thrown out, another complaint, brought by Cheri Pierson in November, accuses Black of a violent sexual assault that left her "swollen, torn, and bleeding."

Epstein died by suicide in prison in 2019 while awaiting trial on sex-trafficking charges. In the years since, several Wall Street financiers and other high-profile figures have come under scrutiny from investigators over their social or professional ties to Epstein.

Last year, in a pivotal moment in the ongoing investigation into Epstein's crimes, his longtime confidante Ghislaine Maxwell was sentenced to 20 years in federal prison for her role in what prosecutors called a yearslong scheme to groom and sexually abuse underage girls.

The latest lawsuit was filed in New York federal court on Tuesday, the same day the Senate Finance Committee said it was investigating whether Black's $158 million payment to Epstein was part of a scheme to avoid paying over $1 billion in federal gift and estate taxes.

Black's legal team responded to Sen. Ron Wyden, who is leading the investigation, in a letter shared with CNN saying that Black "declines" to share additional information with the committee "at this time." Black's spokesperson, Whit Clay, said in a statement to CNN that all the transactions were lawful and that Black has fully paid all taxes owed to the government.

Black previously said that he "deeply" regrets his involvement with Epstein, which he characterized as a professional relationship that included "estate planning, tax and philanthropic endeavors."

Epstein pleaded guilty to two state prostitution charges in 2008 and served 13 months in prison. He was arrested again in 2019 on charges of sex trafficking minors.

In the lawsuit filed by Jane Doe, lawyers say that she was "shipped off" in 2002 to New York City to meet Black, whom Doe recalls being introduced as Epstein's "special friend."

According to her lawyers, Epstein introduced her to Black and instructed her to give him "the same kind of massage that she had to give to Jeffrey Epstein when he ordered her to." The lawsuit says that meant the massage "would involve sexual intercourse and she was expected to strip naked."

Black, who is about 6-foot-4 and 300 pounds, according to the lawsuit, "grabbed her hand so hard that she thought he broke bones," the lawsuit says.

The lawsuit describes the woman's account of being pinned down and assaulted. It says Black called her "demeaning, shameful, disgusting names" while forcing himself on her and causing her "unimaginable pain."

The lawyers are seeking unspecified damages to be determined in trial for the plaintiff, who is now in her 30s.

-—CNN's Elisabeth Buchwald and Ramishah Maruf contributed to this article.