DES MOINES, Iowa (AP) – An Iowa man has pleaded not guilty to murder charges in ambush-style attacks that killed two police officers last month. Scott Michael Greene submitted his written plea in a court filing Wednesday in which he also asked for a speedy trial.

The 46-year-old has been jailed since he was charged last month in the Nov. 1 shootings of Urbandale officer Justin Martin and Des Moines Police Sgt. Anthony Beminio. He faces life in prison if convicted of either count of first-degree murder.

The shootings took place about two miles apart within minutes of each other as both officers were sitting in their patrol cars. Authorities have said that Greene turned himself in hours later, and that a police dog later recovered a high-powered rifle used in the attacks.