A police officer is believed to have attempted suicide at Murakami Police Station in Niigata Prefecture on Sunday, police said.
The officer, 34, was found bleeding from his head and holding a gun in his right hand in one of the station's bathrooms, according to the police.
He was rushed to a hospital, where he was unconscious and in serious condition on Sunday afternoon, the police said.
A police officer who heard a gunshot at around 5:40 a.m. Sunday found the man sitting on a toilet and leaning against the wall in the third-floor bathroom.
The wounded officer was on duty from 9 a.m. Saturday till 9 a.m. Sunday. His colleagues said they did not notice anything unusual about him before the incident.