Powell, whose exploits were detailed by Joseph Wambaugh in the acclaimed "The Onion Field," died Sunday in a state prison medical facility, the Los Angeles Times reported.
Powell and sidekick Jimmy Smith were looking for a store to rob when they encountered plainclothes police officers Ian Campbell and Karl Hettinger March 9, 1963. Campbell and Hettinger had stopped the two men for a broken taillight.
Powell pulled a gun and kidnapped the two officers, taking them to an onion field near Bakersfield, where Campbell was shot in the face. Hettinger managed to escape and found help at a farmhouse.
Powell was arrested as he tried to return to Los Angeles and Smith was apprehended the next day.
Powell was twice convicted and sentenced to die but was spared the death penalty when California's capital punishment law was found unconstitutional in 1972. Smith died several years ago.