Police say the suspect who attacked and wounded a police officer at an outpost in Toyama City, central Japan, was planning to steal a gun from the officer.
The assailant has been identified as 22-year-old Masaki Maeda, a student at the University of Toyama.
Maeda entered the police outpost on Thursday afternoon. He hit the officer in the head with a hammer and slashed his face with a knife.
But the police officer overpowered the assailant and arrested him.
Police say the suspect came to the outpost to supposedly drop off a lost article and then suddenly attacked the officer while he was filling in a form.
Police say Maeda told them that he intended to commit suicide with the gun.
The police officer's head injury was reportedly light.
NHK