Former judge Richard W. Roberts before the start of a ceremony at the federal courthouse in Washington in 2008. A Utah woman alleges in a lawsuit filed in March 2016 that Roberts sexually assaulted her 35 years ago when he was a prosecutor and she was a teenage witness in a high-profile case. Roberts’s lawyers have called the allegations “categorically false.” (Charles Dharapak/AP)

The former chief judge of the U.S. District Court in Washington has asked a judge to dismiss a federal civil lawsuit that accuses him of sexual assault and abuse more than three decades ago.

Richard W. Roberts, who retired in March the same day the lawsuit was filed, said the woman’s claims that she was coerced into having sex are “wholly without merit” and were filed long after the required legal deadlines.

In his first formal response to the lawsuit, Roberts’s attorneys acknowledge he had a “brief, consensual intimate relationship” 35 years ago with the woman, Terry Mitchell. But the rape allegations are false and have “long since been time-barred and must be dismissed,” according to the court filing this week.

When they met in 1981, Mitchell was a 16-year-old eyewitness for the government in a high-profile murder case Roberts was prosecuting in Utah.

In addition to the civil lawsuit Mitchell filed in Salt Lake City, a federal appellate court is reviewing the decision to dismiss a separate “misconduct complaint” against Roberts. The outcome of the review by the Denver-based U.S. Court of Appeals for the 10th Circuit could determine whether Roberts remains eligible to collect his full salary for life.

Roberts, 63, retired early after the U.S. Court of Appeals for the D.C. Circuit certified that he was “permanently disabled” based on a medical report that shows he “suffers from a very serious health condition” that his attorneys have not publicly disclosed.

Mitchell and Roberts met during the trial of Joseph Paul Franklin, who had fatally shot two black men who were jogging with white women through a Salt Lake City park. Mitchell was one of the women and was called as a witness to testify about the death of her friends.

Before filing the lawsuit, Mitchell contacted the Utah Attorney General’s Office, which asked a former federal judge to review her allegations and make recommendations. Former judge Paul G. Cassell concluded the allegations did not support criminal prosecution. Under Utah state law in 1981, Mitchell was old enough to consent to sexual relations with Roberts, who was then an unmarried 28-year-old.

But the judge reviewing the allegations said Roberts “likely” should have disclosed to the defense his sexual relationship with a witness testifying for the government as part of his constitutional duty.

In her lawsuit filed March 16, Mitchell, now 51, says Roberts “intimidated, coerced, and manipulated” her into having sex for weeks and that he picked her up from home or the courthouse to take her to dinner and then to his hotel.

Mitchell says that she repressed all memory of the events until Roberts got in touch with her by email after Franklin was executed in 2013. Roberts’s attorneys say the timing contradicts her statements to law enforcement officials that suggested she was aware of the nature of their relationship during periodic phone conversations she and Roberts had over the years.

Mitchell’s attorney Rocky Anderson said Thursday that Roberts’s attorneys mischaracterized their conversations and what she told investigators.

“It’s a complicated set of emotions when a young person is pulled into something with someone who has immense power,” Anderson said.

Specifically, Roberts’s lawyers, led by Brian M. Heberlig, said that the one-year and four-year statutes of limitations have expired for the 35-year-old allegations.

In 2015, Utah amended state law to allow civil lawsuits to be brought at any time in cases involving “sexual abuse suffered as a child.”

Roberts’s lawyers said in the filing that 2015 law does not apply retroactively. Anderson, Mitchell’s attorney, disagreed. The law was designed, he said, to deal with cases like this one in which “it takes young people sometimes decades to be able to confront the perpetrators.”

If the judge were to hold a hearing, Roberts’s lawyers said, Mitchell would have to present evidence to show she was “not cognizant during the limitations period” of having had sexual relations with Roberts.

In the separate review by the 10th Circuit, the court is considering the D.C. Circuit’s dismissal of a misconduct complaint by the Utah attorney general’s office. Acting chief judge Karen L. Henderson said the complaint had been rendered moot because of Roberts’s retirement.