Although Feinstein had the document for some time and even declined requests from other Democrats on the Senate Judiciary Committee to share the letter, it wasn't until Thursday that she opted to acknowledge it publicly and announce that she had referred it to the FBI.
"I have received information from an individual concerning the nomination of Brett Kavanaugh to the Supreme Court," Feinstein said in a statement. "That individual strongly requested confidentiality, declined to come forward or press the matter further, and I have honored that decision. I have, however, referred the matter to federal investigative authorities."
According to The New Yorker, the allegations stem from a high school party the two attended in the early 1980s. At the time, Kavanaugh was a student at Maryland's Georgetown Preparatory School, and the woman attended a nearby school.
In the letter, it's alleged that Kavanaugh had held the woman down and tried to force himself on her as one of his classmates turned up music in the room in order to drown out her protests. Additionally, Kavanagh also reportedly covered the woman's mouth with his hand.
Though she was ultimately able to escape from Kavanaugh's grip, the alleged incident stayed with her throughout the years. She opted to reach out to her congresswoman, Anna Eshoo (D-CA), and later Feinstein about the incident in July after news of Kavanaugh's nomination began to revive the memories.
While Feinstein has stated that she steered away from publicizing the letter out of concern for the woman's privacy, the New Yorker reported Friday that the San Francisco native "conveyed to other Democratic members' offices that the incident was too distant in the past to merit public discussion." It was also reported that Feinstein felt it was more important to question Kavanaugh on legal matters, not personal issues.
In response to the news of the letter, Kavanaugh has denied all accusations to The New Yorker, saying, "I categorically and unequivocally deny this allegation. I did not do this back in high school or at any time." The unidentified classmate stated he has "no recollection" of the encounter.
White House spokesperson Kerri Kupec called the revelation an "11th hour attempt to delay [Kavanaugh's] confirmation."
Republican Sen. Chuck Grassley, the chair of the Senate Judiciary Committee, released a letter on Friday signed by 65 women who stressed that in the years they've known the nominee, "he has behaved honorably and treated women with respect."
"Through the more than 35 years we have known him, Brett has stood out for his friendship, character, and integrity," the letter reads. "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."
"The signers of this letter hold a broad range of political views. Many of us are not lawyers, but we know Brett Kavanaugh as a person. And he has always been a good person," it concludes.
Similar allegations were brought up in 1991 during the confirmation hearing of Supreme Court Justice Clarence Thomas, who was accused by Anita Hill of sexual harassment. Hill's allegations stemmed from when Thomas was her boss at the Equal Employment Opportunity Commision. Thomas was eventually confirmed by a 52-48 vote.
The Judiciary Committee is expected to vote on Kavanaugh's nomination on September 20. The Senate will vote to confirm him later this month.