Chennai, Oct 8 (IANS): In a shocking incident, a depressed trooper gunned down three security personnel and injured two at the Kalpakkam nuclear complex Wednesday morning, a police official said.

The shooting happened around 5.30 a.m. when Vijay Pratap Singh, a head constable in Central Industrial Security Force (CISF), gunned down three and injured two at their barracks, the police official said.

The incident happened near the township away from the power plant, an official of Nuclear Power Corporation of India Ltd. (NPCIL) that operates MAPS told IANS.

"We have taken the gunner into custody. He is docile and seems to be depressed. It seems he was not satisfied with the working conditions," C. Vijayakumar, Kanchipuram district superintendent of police, told IANS.

He said one of those killed, Mohan Singh, was allotting duties and Vijay Pratap Singh was not happy with him.

Early in the morning, Vijay Pratap Singh gunned down Mohan Singh at his place and while coming down the staircase he shot the others, killing Ganesan and Subburaj and injuring two others.

The injured have been admitted to a private hospital and the condition of one of them is said to be critical.

"It was a lady security personnel, Shobha, who brought the depressed gunner to a room and informed others," Vijayakumar said.

He said the investigation is on.

According to officials of Madras Atomic Power Station (MAPS) at Kalpakkam, the unfortunate shooting has not affected the nuclear power plant or its operations.