A man who killed six people, including a sheriff's deputy, in a northwest Washington shooting rampage last year pleaded guilty Tuesday and will spend the rest of his life in a mental hospital or prison.

Isaac Zamora entered the pleas to 18 charges, including aggravated murder, attempted murder and burglary, after prosecutor Rich Weyrich agreed he would not seek the death penalty.

"Mr. Zamora won't ever walk the streets again," Weyrich said. "From a public safety standpoint, we've accomplished that."

Zamora, 29, began his rampage Sept. 2, 2008, near the town of Alger, 70 miles north of Seattle, and continued it on Interstate 5. Described by his family as mentally disturbed, he was captured after a police chase and later told investigators he killed for God.

The dead included a man who had accused Zamora of trespassing, a woman who lived nearby, two construction workers, a motorist on the highway, and Skagit County Deputy Sheriff Anne Jackson. Jackson had frequently tried to help Zamora's family deal with his mental illness, Zamora's mother said.