Four days before the Fourth of July, a Lehi man got an unwanted fireworks demonstration when a homemade pipe bomb blew up in his hand, according to police.

Lehi police responded to Potter's home near 300 West and 300 North on Monday night after getting a report of a possible self-inflicted gunshot wound. Witnesses told the officers that they heard a loud boom then saw Potter run out of a shed in his back yard and fall to the ground in pain, according to an affidavit filed by police in Provo's 4th District Court.

Potter had streaks of blood on his stomach and his wife started spraying him off with a water hose, the witnesses told police, according to the affidavit. He received stitches on his hand at American Fork Hospital.

Police initially suspected that the shed housed a methamphetamine lab. But after getting permission from the property owner, Potter's mother, to cut the padlock, they found evidence of explosives, including what appeared to be an exploded section of pipe, a metal pipe with a screw-on cap, opened rifle ammunition, sealed PVC pipe and a timer with duct tape and wires, the affidavit said.

After being released from the hospital, Potter told police that he and two friends were in the shed, where he was packing explosive material into a metal pipe, the affidavit said. Potter said he put the contents of emptied-out firecrackers, fireworks and rifle rounds into a pipe casing and was packing the gunpowder down with an ice pick when the pipe exploded, police wrote.

Potter said he did not intend to harm anyone.

Potter's 5-year-old son told police that Potter was holding a cup that exploded in his hand, the officers wrote in the affidavit. Potter said his son was not in the shed.