In a surprise reversal, both state and county authorities moved to oppose the release of a convicted serial rapist, effectively quashing a long and highly politicized sex offender case.

Thomas Duvall, 58, a rapist who has admitted to attacking at least 60 women, withdrew his petition for provisional discharge from the Minnesota Sex Offender Program (MSOP) on Monday after both Human Services Commissioner Lucinda Jesson and an assistant Hennepin County attorney filed letters to the court last week saying they opposed Duvall’s provisional discharge.

The developments, coming less than two months before the election, raised immediate questions about whether the state was bowing to political pressure in opposing Duvall’s release. A four-day public hearing, in which the state was expected to lay out its case for Duvall’s provisional discharge, was scheduled to begin Tuesday but was canceled late Monday.

The about-face by the state is a victory for the attorney general’s office, which had sought to block Duvall’s release after raising alarms about the number and horrific nature of his assaults. Duvall was convicted on three separate occasions of sexually assaulting teenage girls — each time shortly after he was released from prison — in cases with gruesome and violent details.

The day after Christmas in 1987, Duvall bound a 17-year-old girl with an electric cord and repeatedly raped her over a three-hour period while hitting her with the handle of a hammer, according to court documents.

However, in August 2013, a special Department of Human Services review board concluded that Duvall had shown enough progress in treatment to recommend that he be granted provisional discharge with certain conditions from MSOP. Hennepin County did not object to the board’s recommendation.

Minnesota Attorney General Lori Swanson

“Eleven months ago, the officials with statutory authority supported the release of Mr. Duvall,” said Attorney General Lori Swanson. “Only by a twist of fate was this office able to intervene. It is unfortunate that Mr. Duvall put his victims through 11 months of hell before withdrawing his petition a day before the hearing.”

A sister of the survivor of the 1987 assault said her family was “elated” by the news. The family, she said, relives the horror of her rape every year at Christmas. “There are no words to express how relieved our family is at this time,” said the sister, who asked that her name not be used in case Duvall is ever released. “Our family has been through a nightmare, particularly over the past year” since Duvall’s petition became public.

A Department of Human Services spokeswoman declined Monday to comment on the agency’s change of position. In a Sept. 12 letter to the court, Jesson wrote only that the decision to oppose Duvall’s provisional discharge was “based upon the totality of information currently available.” Assistant county attorney Theresa Couri used the same language in her letter to the court.

The absence of a clear explanation Monday for the state’s 11th-hour reversal contributed to the perception that the state was reacting to political pressure. Over the past year, Republicans have repeatedly lashed out at Gov. Mark Dayton for not opposing Duvall’s release, prompting Dayton’s office to suspend the provisional release of any clients at the state sex offender program until the state Legislature reviewed the program.

“The evidence suggests that political aspects of [Duvall’s] release might have had some impact,” said Eric Janus, dean of William Mitchell College of Law. “If so, then that’s very unfortunate, and demonstrates one of the key flaws of this whole system, that it’s so susceptible to being politicized.”

The Duvall case highlights the challenges the state faces in its handling of nearly 700 rapists, pedophiles and other offenders housed at prisonlike treatment centers in Moose Lake and St. Peter. The state is under mounting legal pressure from a federal judge to show that it has a viable system for treating and releasing offenders, who have already served their prison time. A class of sex offenders has sued the state, alleging that MSOP violates their due process rights by failing to provide sex offenders with effective treatment and the opportunity for release.

The fact that just two offenders have been conditionally released from the program in its 19-year-history has been cited as evidence that the program is dysfunctional and is violating offenders’ due process rights. Minnesota has the highest per capita number of civilly committed sex offenders of any state that uses civil commitment.