Sen. Ben Sasse sent a letter to the head of the Federal Bureau of Prisons telling her to “come prepared” with answers regarding the death of convicted sex offender Jeffrey Epstein.

“Epstein’s death makes it significantly harder to prosecute his co-conspirators,” the Nebraska Republican said in a letter dated Wednesday to Kathleen Hawk Sawyer. “Wealthy and powerful men raped innocent children, and it is an outrage that so much of the evidence of these crimes died with Epstein while in your agency’s custody.”