SALT LAKE CITY (AP) — A former federal judge in Washington, D.C. won’t face judicial discipline over allegations he sexually assaulted a woman when he was a prosecutor in Utah and she was a 16-year-old witness in a white supremacist serial-killer case, according to court documents.

A panel of federal judges found they couldn’t punish Richard W. Roberts because he wasn’t yet a judge when he met the teenage girl during the 1981 Utah trial in the deaths of two black joggers.

Roberts has acknowledged having an intimate relationship with the teen, but says it was consensual and began after the trial. His lawyer Brian Heberlig declined to comment Friday on the decision.

The Utah Attorney General’s Office expressed disappointment about the complaint being dismissed by the U.S. Judicial Conference’s Committee on Judicial Conduct and Disability.

“Would we have liked to see them do more? Yes,” said attorney general spokesman Dan Burton. State prosecutors decided to file the ethics complaint instead of criminal charges, in part because 16 was the legal age of consent at the time.

Congressional oversight committees could still impeach Roberts, Burton said, though he wasn’t immediately aware of any efforts to take up the case.

Roberts announced his retirement as chief judge for the U.S. District Court for the District of Columbia in March 2016, the same day the allegations came to light in a lawsuit.