WESTMINSTER, Colo. -- A Westminster police officer who killed a suspected prowler in a controversial off-duty shooting has been cleared of any wrongdoing and has resigned.

Officer Karl Scherck resigned a day after a review board concluded that Scherck's actions were lawful, reasonable and consistent with the procedures and rules of the Westminster Police Department. Westminster police spokesman Tim Read said Scherck resigned for personal reasons.

Scherck was involved in two fatal shootings -- and cleared in both -- in the past year.

The most recent shooting happened Sept. 22. Scherck said he was mowing his mother's law when he saw a man prowling the neighborhood, trying doors and looking in windows.

Scherck, out of uniform, confronted the man, telling him he was a police officer. He said the man came at him with a sharpened fence picket.

Scherck shot and killed 47-year-old Sergio Alejandro Medrano, an ex-convict.

The administrative review investigated whether Scherck violated any departmental procedures or rules when he chose first, to become involved in thwarting the felony burglary in progress, and secondly, to use lethal force. The police department's Complaint Review Team that cleared him is made up of two people from the community, one appointed by the city manager, and one appointed by the city's personnel board, along with a police lieutenant and a police sergeant.

The district attorney said last month that he would not prosecute Scherck for the shooting but said he was unhappy with the way the officer handled the confrontation.

Crime scene evidence showed Sherck fired three shots and Medrano was hit in the shoulder, arm, chest, knee and a finger. District Attorney Bill Ritter's criticism focused on Scherck's willingness to expose himself and the suspect to "an unnecessary and unacceptable risk."

Scherck was not in uniform and was wearing a shirt that had the words, "Fraternal Order of Rapid Fire" during the shooting.

Scherck also was involved in a shooting 150 days earlier, when he shot a man who drove his van at another Westminster police officer.