A 57-year-old assistant commissioner of police (ACP) allegedly shot dead his wife and nephew with a gun before shooting himself fatally at his home in Maharashtra`s Pune city on Monday, an official said.

The incident took place at around 3.30 am at ACP Bharat Gaikwad`s bungalow in Baner area. The reason behind the incident was yet to be ascertained, the official from Chaturshringi police station said.