A western Iowa man is headed to federal prison for possession of a homemade hand grenade.

Federal prosecutors in Iowa say 38-year-old Alan Lee Heath of Harlan was sentenced Friday to 30 months in prison for possessing a destructive device. U.S. District Court Judge James Gritzner also ordered Heath to serve two years of supervised release once his prison term ends.

Authorities says Heath was stopped by two Shelby County Sheriff’s deputies in December, after he was seen trespassing at a private residence. Deputies say they had to subdue him, and a search of his person found a device that included a plastic cylinder with gun powder, wrapped with electrical tape. The device had .22-caliber bullets taped to the outside.