DES MOINES, Iowa (AP) — Prosecutors say a man who pleaded guilty to killing two police officers in Iowa simply disliked law enforcement.

Polk County Attorney John Sarcone said during a hearing Friday that Scott Michael Greene drew a "to do" list in his jail cell that amounted to a hit list. The list included the names of three sheriff's deputies, as well as the names of the two slain officers, with checkmarks by their names.

Greene pleaded guilty Friday morning to the shooting deaths of Urbandale officer Justin Martin and Des Moines Sgt. Anthony Beminio. He was immediately sentenced to life sentences for two counts of first-degree murder.

Sarcone says evidence shows Greene bought a bottle of whiskey at a convenience store before he took a loaded assault rifle and shot the first officer he encountered on a street early on Nov. 2, 2016. The officers were killed as they sat in their patrol cars, about 2 miles apart.