TACOMA, Wash. -

A state court of appeals has upheld the 420-year prison sentence given to the getaway driver for the man who ambushed and killed four Lakewood police officers.

Darcus Allen was convicted of four counts of aggravated murder for his role in the November 2009 shooting. He appealed, arguing that a prosecutor misstated the legal definition of "knowledge" when he accused Allen of knowing that Maurice Clemmons planned to shoot the officers.

Allen drove Clemmons to the scene, waited and drove him away. Clemmons was killed two days later in a confrontation with a Seattle police officer.