Sgt. Kevin Allais (Al-LAYS) said Kenneth S. Garrison was arrested Wednesday at a motel in east Portland, Ore. A Portland-area SWAT team and suburban Gresham police assisted Clark County officers.
Allais says the victim is a relative of Garrison's.
The sheriff's office says Garrison resigned from his lieutenant's position last month. He also served as a lieutenant colonel in the Washington Army National Guard but retired on Monday.
Garrison is expected to appear Thursday in Multnomah County court in Portland. It was not immediately known whether he was represented by a lawyer.
The sergeant says the investigation is continuing.