A convicted serial rapist being evaluated for possible release will not face legal sanctions for destroying personal journals that described his violent sexual fantasies.

A state Supreme Court appeals panel ruled Wednesday that Thomas Duvall, 58, was under no legal obligation to retain his personal journals after the state approved his petition for provisional discharge in 2013. Duvall kept the journals, or “fantasy logs,” as part of his therapy at the state sex offender treatment center in St. Peter.

The decision not to sanction Duvall, who sexually assaulted teenage girls in the 1970s and 1980s, is a victory for civilly committed sex offenders and their advocates, who have argued that offenders should be allowed to document their inner thoughts and experiences for therapeutic purposes without fear that their writings could be used against them in court.

The ruling also deals a blow to efforts by Attorney General Lori Swanson’s office, which opposes Duvall’s conditional release, to portray him as dishonest and untrustworthy. Swanson’s office alleges that Duvall lied about the timing and circumstances of his destruction of the fantasy logs in an attempt to hide violent and deviant thoughts that might prevent his release.

Responding to the ruling, a spokesman for the Attorney General said Duvall had a history of using “brutal force and deceit” to overpower his victims. In 1987, just 12 days after he was released from prison, Duvall tied up a 17-year-old girl with an electrical cord and repeatedly raped her while hitting her with a hammer. The girl had let Duvall into her apartment after he asked to use the phone.

“We continue to be deeply troubled that Mr. Duvall destroyed these records because we believe they are highly relevant to his need for commitment and to public safety,” the spokesman said.

The Duvall case has become a politically charged flash point in the debate over the future of the Minnesota Sex Offender Program (MSOP), which confines about 690 rapists, pedophiles and other offenders in prisonlike treatment centers in St. Peter and Moose Lake.

The state faces a quandary. It is under mounting legal pressure from a federal judge to show that MSOP is a viable system for treating and releasing offenders. If no one completes treatment, the program can be struck down as unconstitutional for depriving offenders — who have already served their prison time — of their due process rights. However, when special review panels approve offenders for conditional release, details of their horrific crimes surface and elected officials get cold feet for fear of being attacked as soft on crime and insensitive to sexual assault survivors.

A ‘political circus’

Late last year, Republican lawmakers excoriated Gov. Mark Dayton for not opposing MSOP’s plan for a supervised discharge of Duvall, who has admitted to attacking more than 60 women. In response, Dayton lashed out at what he called the “political circus” surrounding Duvall’s proposed discharge, and ordered state officials to suspend future releases of offenders until the Legislature reviewed the sex offender program.

However, the Legislature failed to act this spring, putting MSOP’s future in the hands of a federal judge hearing a constitutional challenge to the program. The sex offenders have sued the state as a class, arguing that being civilly committed in Minnesota amounts to a life sentence because the treatment is inadequate and almost no one is ever released. Only two offenders have been provisionally discharged from the program in its 19-year history.

The controversy over Duvall’s fantasy logs has broad implications for the treatment of convicted sex offenders. It is common practice for psychologists to encourage violent offenders to maintain personal journals as a way of tracking their deviant thoughts and experiences. The mere act of keeping a journal can be therapeutic, particularly for offenders who struggle to communicate in group sessions, say psychologists. Not keeping a journal, when it is made part of an offender’s treatment plan, can be used against the person at a release hearing.

Therapy vs. evidence

Attorneys for Duvall argued that the inclusion of the fantasy logs as public evidence would have a “chilling effect” on the treatment process.

“It is patently unfair to require journals and require honesty in these journals, only to have the journals used against you later,” said Dr. Michael Thompson, a psychologist and president of the Minnesota Association for the Treatment of Sexual Abusers, which represents mental health professionals who treat sex offenders.

Personal journaling had been a part of Duvall’s treatment program for several years. In 2012, a doctor appointed by the state concluded that Duvall should not be released, based in part on a preoccupation with sexual violence exhibited in his fantasy logs, court documents show. The doctor, David Thornton, wrote in a report that Duvall’s fantasy logs showed “a frequent need to interrupt offense-related sexual thoughts and fantasies related to juveniles and sexual violence.”

The appellate court panel ruled that Duvall was consistent in saying that he had no reason to keep the logs because he had already been approved for provisional release to a halfway house and did not expect further litigation.

The judicial panel noted, however, that the attorney general’s office is still free to argue about the content of the fantasy logs and to make inferences based on Duvall’s destruction of them. A four-day hearing considering Duvall’s conditional release is scheduled for Sept. 16. It is expected that some survivors of Duvall’s assaults will attend the hearing.