Thomas Duvall has spent the past 30 years locked up for a series of brutal rapes of teenage girls in the 1970s and 1980s.

Yet in the second consecutive day of testimony before a state Supreme Court panel, this serial rapist has been depicted by therapists and others as a reformed man who is contrite about his violent past and ready for return into the community.

The man who in 1987 bound and raped a 17-year-old girl while beating her with a hammer was described, at varying points Wednesday, as "polite," "calm" and even "empathetic" by those who have counseled or worked with him over the years.

"Tom is actually a very, very gentle guy, once you get to know him," said Tommy Jones, who facilitates a support group with Duvall at the Twin Cities Men's Center in south Minneapolis, who testified Wednesday.

"He's a perfect example of how someone can benefit from treatment."

The picture of Duvall as a model detainee is expected to change dramatically, however, on Thursday once the state begins to present its case against him.

Thomas Duvall left his hearing in Hastings on Wednesday.

Duvall himself is expected to take the stand and face questioning about his horrific crimes and his own writings, in which he describes thoughts of violent fantasies. He may also be asked about his difficulties passing lie detector tests designed to verify whether he is being truthful about his own sexual thoughts.

The State Attorney General's office, which is arguing against his release, says Duvall showed deceptive responses in five of his last six polygraphs.

That includes one taken just last month, when Duvall was asked about masturbating to deviant sexual thoughts.

Duvall, 61, sparked a political firestorm three years ago when staff from the Minnesota Sex Offender Program (MSOP) recommended him for a conditional discharge after years in detention. Minnesota Attorney General Lori Swanson and others argued that Duvall was still a danger to the public; Gov. Mark Dayton intervened and Duvall eventually withdrew his petition.

The Duvall trial, which began Tuesday, has highlighted the contentious and often Byzantine nature of Minnesota's system of committing hundreds of sex offenders after they have already served their prison terms.

In this case, officials employed by the state agency that oversees the MSOP are themselves taking opposing positions at times. Human Services Commissioner Emily Piper has said she "strongly opposes" Duvall's petition for conditional discharge, but multiple members of Duvall's treatment team, and others at the MSOP, have said Duvall has shown significant progress and deserves to be released.

Meanwhile, a court-appointed forensic psychologist, Dr. James Alsdurf, has said in a report that he opposes Duvall's petition after an extensive review of his treatment history. Alsdurf reached that conclusion after reviewing more than 10,000 pages of Duvall's records dating back 40 years. Alsdurf's report was filed under seal with the court and is not public.

Under pressure from a lawsuit and a federal judge, the state has been striving to show that the MSOP is actually a treatment program that shows results and not an indefinite — and unconstitutional — form of detention. Since Duvall's first petition failed, state judicial panels have granted supervised release to a dozen other offenders who have completed treatment and received strong endorsement from treatment professionals.

Duvall, who was committed to the MSOP in 1991, has already been accepted by Zumbro House Inc. of Woodbury, which provides community housing to sex offenders and others with behavioral problems. Zumbro House currently houses five sex offenders who have been provisionally discharged from the MSOP since 2012.

Chris Serres • 612-673-4308