Police seized six homemade bombs Monday from the home of a 33-year-old Fukui man who was critically injured when one of the explosives blew up prematurely.
According to police, the explosion took place at around 5:30 a.m. Sunday in a parking lot beside a building that served as a pharmacy and residence.
Shrapnel scattered as a result of the blast and a wall of the building was charred, police said.
The man, whose identity was not disclosed, was quoted as telling investigators who arrived at the scene that the bomb was hand-made and that he learned how to make the explosive s via the Internet. Police said it appears the man made a mistake when handling the timing device. He was hospitalized with serious burns over his entire body.