Federal prosecutors accidentally returned an external hard drive to former DOJ lawyer Jeffrey Wertkin that contained the 40 whistleblower cases he pleaded guilty to stealing and trying to sell, according to a letter Wertkin sent to the judge overseeing his case.

In a letter dated March 16 and posted to the docket Wednesday afternoon, Wertkin informed U.S. District Judge Maxine Chesney that after his sentencing hearing, prosecutors returned the hard drive which had been seized from him when he was arrested wearing a wig in a Cupertino hotel lobby last year. Wertkin, who was a partner at Akin Gump Strauss Hauer & Feld at the time, said he didn’t realize what the hard drive contained until he opened it to find the 40 sealed complaints.