A federal judge has rebuked the U.S. attorney's office in Minnesota for seeking the civil commitment of a sex offender in 2006 despite assessments by federal prison system authorities that he was not a candidate for civil commitment and would be manageable in a halfway house.

In an order filed Monday, U.S. District Judge Paul Magnuson said that in light of just-disclosed documents, the attempt by federal prosecutors to have inmate Roger Dean Tom committed was "inexplicable" and their rationale for continuing to try to prevent his release "nothing short of remarkable."

"Granting the government's motion would violate not only logic but the law," Magnuson wrote in denying a motion by prosecutors to further delay Tom's release from the Federal Medical Center in Rochester.

Tom pleaded guilty in Utah in 1997 to aggravated sexual abuse and was sentenced to 10 years in prison and five on supervised release. He was transferred to the Rochester facility to serve out the end of his term.

The order was the second blow Magnuson dealt the office in two weeks. In late May he ruled that Congress exceeded its authority when it allowed federal officials to commit allegedly mentally disordered sex offenders to treatment centers at the time of their release from prison.

In so doing, Magnuson threw out a petition by Rachel Paulose, former U.S. attorney for Minnesota, to civilly prolong inmate Tom's confinement. Paulose had blocked Tom's scheduled release in October 2006 by petitioning the court to have him declared a sexually dangerous person under the Adam Walsh Child Protection and Safety Act, which had been passed just three months earlier.

Magnuson's ruling was the fifth nationally by district judges on the law; three ruled it valid, and two found it unconstitutional. An Appeals Court has yet to decide the issue.

Federal prosecutors had filed a request that Magnuson stay his ruling while they decide whether to appeal. In his order Monday, Magnuson rejected that request.

Magnuson's order said that in arguing against the stay, Tom's federal public defender produced a September 2006 letter from a regional federal Bureau of Prisons official to the warden in Rochester, saying that a review of Tom's file showed he didn't qualify for commitment and "should be released." Also produced for the first time, Magnuson said, was a report that month from the prison's staff psychiatrist, saying the staff believed Tom "will be able to handle halfway house placement."

"On this record, the court finds the government's motion for a stay to be wholly unsupported, and the denial of supervised release inexplicable," Magnuson wrote.

He added: "The only factor more perplexing to the court is how and why it took a year and seven months for anyone to seek relief on Tom's behalf."

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