A woman is suing controversial Harvard law professor Alan Dershowitz for defamation in relation to an ongoing sexual abuse case involving his client, billionaire sex offender Jeffrey Epstein. Virginia Giuffre—who alleges Epstein sexually abused and trafficked her in the early 2000s starting when she was 16 years old—says that Dershowitz participated in the sex trafficking, and accuses him of later falsely claiming she fabricated the accusations and that he had never met her.

The lawsuit, filed in the Southern District of New York Tuesday, brings to light an affidavit by Maria Farmer, a former employee of Epstein’s who says she frequently witnessed school-age girls coming to Epstein’s New York City mansion, and that on a number of occasions Dershowitz would “go upstairs” with the underage girls. Dershowitz has denied the claims. Farmer also revealed she and her sister were also assaulted by Epstein, as well as his alleged madam, Ghislaine Maxwell. She was 26 at the time of the alleged assaults in 1996, and her sister just 15. Dershowitz, who is a close friend of Epstein’s, helped him secure a plea deal after he was arrested in 2006 for sexually abusing dozens of underage girls in Florida.