The police officer who was stabbed in Osaka Prefecture early Sunday morning remains unconscious.
Police say the officer's loaded gun was stolen. They are searching for the attacker and are calling on people to stay inside and lock their doors.
Twenty-six-year-old Suzunosuke Kose was found by staff from a nearby train station with a kitchen knife in the left side of his chest at around 5:30 a.m. in front of Senriyama police box in the city of Suita.
Police say he had multiple stab wounds and that a hook to prevent officers' guns being stolen was unlatched.
Investigators say three officers were on duty overnight but two were called away to respond to a telephone call about a theft nearby.
They suspect Officer Kose was attacked when he was about to leave.
They say the call came from a public phone and was likely a hoax.
Surveillance camera footage shows a man, apparently in his 30s and wearing a dark top, white tee shirt, and dark pants, loitering around the police box.
They are investigating the case as a robbery and attempted murder.