Kolkata, Dec 26 : A Kolkata Police constable died at a city hospital in the wee hours on Tuesday, after he shot himself from his service revolver before leaving for his night-shift duty on Monday night. The deceased constable has been identified as Tapan Paul (53), a resident of Haringhata in Nadia district of West Bengal. He used to stay at the police barrack in the same building in central Kolkata which houses the office of the state food & supplies department. He was attached to the reserve force of the city police. City police sources said that on Monday night while he was boarding the car to move to his place of duty for the night-shift, he suddenly brought out his service revolver and shot himself. He was shifted to the hospital where he died later. Initial investigation had revealed that Paul was suffering from acute mental depression for quite some time. Some of his colleagues also informed that he was suffering from some nervous system-related ailments also. The police have seized the service revolver which the deceased used to shoot himself. The local New Market Police Station has registered a case of unnatural death in the matter. A detailed investigation in the matter has also been initiated. /IANS