PITTSBURGH — The gunman in a fatal shooting rampage inside a psychiatric clinic was previously committed to a mental health facility for following an altercation with police in Oregon in 2009, a prosecutor said.

Details of John Shick’s previous involvement with mental health professionals come as investigators piece together a motive for last week’s shooting that killed one person and wounded six others in the lobby of the Western Psychiatric Institute and Clinic at the University of Pittsburgh.

After the arrest Dec. 29, 2009, a judge ordered Shick, at the time living under a different name, to undergo up to 180 days of mental health treatment, Multnomah County Deputy District Attorney Robert Leineweber told a Pittsburgh newspaper today,

Shick was killed Thursday in an exchange of gunfire with University of Pittsburgh police.