SEATTLE, Wash. -

A federal judge has dismissed a gun charge against a man who was convicted of murder as a teenager, saying state Department of Corrections officers improperly withheld information that could have been helpful to his defense.

Robert Andre Frazier served 34 years in prison for taking part in the fatal beating of an elderly man outside a Bremerton restaurant in 1981, when he was 15. He was released last summer, but a few months later he was back in custody, after a confidential informant tipped off corrections officers that Frazier had armed himself with a revolver and was seeking revenge for his uncle's recent murder in Renton.

U.S. District Judge Richard Jones wrote in an order this week that the corrections officers had a duty to disclose that they were aware of serious credibility issues with their confidential source. He called the government's actions "unabashedly negligent."

Frazier is still in custody on parole violations.