Spurred by Susan Brigham and other members of the slain psychiatrist’s family, Sen. Patty Murray is leading a bipartisan group of lawmakers in demanding the Air Force explain how the tragedy occurred.

The group also wants some proof changes are being made.

“We have concluded that significant mistakes were made and that the Air Force missed important opportunities in their handling of the Mellberg case,” the 13 lawmakers wrote in a letter last week to Defense Secretary William Perry.

The mistakes they list echo an investigation by The SpokesmanReview last fall.

That military mental health experts recommended gunman Dean Mellberg’s discharge long before Maj. Thomas Brigham and Capt. Alan London sent him to Texas, and that Wilford Hall doctors recommended his discharge. Other officers overrode those recommendations.

That Mellberg was given a clerical job at Wilford Hall which allowed him to review his own psychiatric records - and possibly target the doctors who recommended his discharge. While unsupervised, Mellberg apparently stole some of his records from the files.

That his subsequent discharge from Cannon Air Force Base in New Mexico was done quickly, and apparently with no regard to his longstanding mental illness.

Within a month of his discharge, he returned to Spokane, bought a semiautomatic assault rifle and committed the community’s worst massmurder before being killed by a Air Force policeman. His first two victims were London and Brigham.

Murray, D-Wash., holds out the possibility of congressional hearings if the military tries to stonewall on the Mellberg case.

“We have to have better safeguards,” she said. “Maybe some good will come of this tragedy in the future.”