MOSCOW, April 27 (RIA Novosti) - A senior police officer shot three people dead during the night and injured six others in a store in southern Moscow, Russia's top investigators said on Monday.

"At about 00:30 Moscow time, Denis Yevsyukov killed the driver of a Chevrolet Lanos who dropped him at the store," Investigation Committee spokesman Vladimir Markin said. "The police officer then entered the supermarket and opened fire, killing a female cashier and a man, and injuring six others. He was arrested."

Earlier reports said Yevsyukov, police chief of the capital's Tsaritsino district, had killed two people.

Investigators have not given information on possible motives for the shooting spree.

A police source told RIA Novosti that Yevsyukov has been taken to a psychiatric clinic for examination.