Threat preceded Seattle officer's slaying

SEATTLE, Nov. 4 (UPI) -- Seattle police found a threatening note nine days before an officer was shot dead in his patrol car last weekend, police sources said.

The sources told The Seattle Times the note, which threatened the lives of Seattle officers, was discovered Oct. 22 at a city maintenance yard where four police vehicles had been set on fire, apparently by pipe bombs.

Officer Timothy Brenton was shot and killed Saturday by an assailant who pulled alongside his patrol car and opened fire.

It was not known if the shooting, which slightly wounded Brenton's rookie partner, was related to the note, the newspaper said Wednesday. Police officials told the Times this week they had received multiple tips from the public claiming a connection.

Police were looking for a "vehicle of interest" that was photographed by the dashboard camera on Brenton's car. An officer-safety bulletin issued to the force Tuesday said there was no probable cause to arrest the occupants, but warned officers to use extreme caution if the found the vehicle.

The Seattle Police Officers Guild and Seattle Firefighters Union said Wednesday a reward for information leading to an arrest and prosecution of Brenton's killer has grown to $105,000, KATU.com reported.