A prosecutor says he'll seek the death penalty against the man accused of killing a Seattle police officer on Halloween.

Christopher Monfort has pleaded not guilty to first-degree murder in the shooting death of Officer Timothy Brenton.

King County Prosecutor Dan Satterberg filed notice Thursday that he would seek the death penalty if Monfort is convicted.

Investigators say Monfort drove alongside Brenton's cruiser as it was parked and opened fire, killing Brenton instantly and grazing the neck of his partner, Brit Sweeney.

Monfort also is charged with arson and attempted murder for the firebombing of several police vehicles in a maintenance yard on Oct. 22 — the first step in what prosecutors called Monfort's "one-man war" against Seattle police.