DENVER -- A 33-year-old Loveland mail carrier has been indicted by a federal grand jury on charges of mail theft and possession of a machine gun, prosecutors said.

Jason W. Muchow appeared in federal court Monday morning.

Muchow was a letter carrier who worked at the Valentine Station in Loveland, said Acting U.S. Attorney David M. Gaouette.

According to the indictment, from Dec. 9, 2008 to Feb. 7, 2009, Muchow possessed stolen first-class mail addressed to a former girlfriend and was in possession of a fully automatic AK-47. Unregistered fully automatic weapons, sometimes called machine guns, are illegal.

Muchow was arrested on Feb. 7, 2009 on charges of breaking and entering into the woman's apartment, Gaouette said. According to court records, he allegedly killed and mutilated his ex-girlfriend's cat.

When investigators searched Muchow's home, they found the AK-47 in Muchow's bedroom, along with ammunition, Gaouette said.

"Illegally possessing a prohibited weapon, especially a fully automatic AK-47, is a serious crime that will not be tolerated in our community," Gaouette said.

If convicted, Muchow faces up to five years in federal prison and up to a $250,000 fine for each of the two counts of mail theft. He also faces up to 10 years in prison and a $250,000 fine for possession of a machine gun.

The Office of the Inspector General for the U.S. Postal Service, the Bureau of Alcohol, Tobacco, Firearms, and Explosives and the Loveland Police Department are all investigating the case.