Thousands of not-yet public documents from Joe Biden’s nearly 40-year congressional career may hold the key to the sexual assault allegation being leveled against the former vice president.

Late last month, Tara Reade, who came forward in April 2019 to accuse the former vice president of unwanted touching and sexual harassment, revealed there was more to her story. Reade now claims he pushed her up against a wall and forcibly penetrated her with his fingers, while she was briefly employed by his Senate office in the early 1990s.

The purported assault, which Reade claims took place either in the U.S. Capitol or the Russell Senate Office Building in 1993, has been vehemently denied by the former vice president’s campaign. The denial has been echoed by Biden allies, including onetime members of his Senate staff.

Some, like Ted Kaufman, who was Biden’s Senate chief of staff when the incident allegedly took place, denies that Reade ever mentioned sexual harassment.

“She did not come to me,” Kaufman said recently. “I would have remembered her if she had, and I don’t remember her at all.”

Reade, however, contends that there is official documentation to back up her timeline of events. Not only does she claim to have raised accusations of sexual harassment while on Biden’s staff, but she also filed written report with the Senate personnel office laying out the supposed misconduct.

To date, Reade has not been able to obtain a copy of the personnel report. She claims her inability stems from the fact that Biden’s Senate papers were donated to the University of Delaware in 2011. Those papers now present perhaps the best and clearest record of what really transpired, given the differing recollections between Reade and members of Biden’s camp.

The only problem is that the documents are unlikely to become public any time soon. The documents, which fill 1,875 boxes and include 415 gigabytes of electronic records, were to be made public on Dec. 31, 2019, according to an agreement the former vice president entered into with the University of Delaware upon donating his papers.

Those parameters, though, were changed on April 24, 2019—the day before Biden declared his 2020 campaign—when the university announced the trove of documents would now be made public on Dec. 31 or “two years” after the former vice president “retires from public life.” At the time, the university provided no definition for what it considered “public life,” leaving open the final date for release.

Among the documents are “committee reports, drafts of legislation,” and official correspondance. It is uncertain if documents pertaining to personnel issues or employment complaints would be among the papers. The secretary of the Senate did not respond to a request for clarification about private versus public employment documents by press time.

Even without such information, it is likely that any internal correspondance regarding Reade or her allegations by Biden’s Senate staff would be included. This is especially likely given Reade’s claims of having discussed her accusations with superiors and the hasty nature in which she left her position after the alleged assault took place.

It is unclear if the former vice president will opt to make his papers or at least those relating to Reade public. Requests for comment by the Biden campaign were not returned before press time.