MONROE — The Monroe Police Department was evacuated for about an hour Friday afternoon after what looked like a pipe bomb with a wire sticking out of it was discovered while investigating a suspect’s bag.

When police arrested a Monroe man Friday morning, his backpack was taken to the department at 818 W Main Street to be processed. While searching it at about 1:45 p.m., an officer found an incendiary device, Monroe Police Administrative Director Debbie Willis said. The building was evacuated and the bomb squad arrived to defuse the device.

The department was reopened at about 3 p.m.

The bomb is commonly used on gopher holes, police said.

A photo of the man’s backpack shows a hatchet, propane tank and torch, several needles, a rubber tube, a serrated knife, and assorted personal items. It’s unclear if he’ll face drug charges, Willis said. The 24-year-old man is homeless, authorities said.

Officers encountered the man at about 5:30 a.m. Friday on Railroad Avenue off East Main Street. Police were responding to a potential vehicle prowling, Willis said. The man had several outstanding theft warrants from the Snohomish County Sheriff’s Office and was arrested. After booking the man into jail, officers took his bag and brought it back to the station.The man is not a suspect in the prowling.

Joseph Thompson: 425-339-3430; jthompson@heraldnet.com. Twitter: @byjoeythompson.