Federal prison inmate Jay Abregana, held behind bars for more than a year beyond his release date, is now a free man after the government abandoned efforts to involuntarily commit him to a mental institution for sex offender treatment and evaluation.

The U.S. attorney's office invoked a new federal law — for the first time in Hawai'i, and just the second time nationally — in trying to brand Abregana as a sexually dangerous offender unable to control his desire to have sex with minors.

But federal District Chief Judge Helen Gillmor ruled last week that the government had not proved its case against Abregana, 38, and she ordered him released from custody.

Abregana was convicted in 2002 of sending child pornography through the mail. He was also convicted the same year of a state charge of misdemeanor sex assault against a 12-year-old boy in Hilo.

He finished serving his prison and parole terms in July 2007 but stayed in custody while the Justice Department pursued its claim that Abregana should be held in a mental facility indefinitely — perhaps for the rest of his life.

The U.S. attorney's office last week asked Gillmor to delay Abregana's release until it decided whether to appeal the judge's release order.

Yesterday, Assistant U.S. Attorney Lawrence Tong filed papers in court saying the Solicitor General's office had decided not to appeal.

Gillmor ordered Abregana released from the Federal Detention Center.