The accused, Sayyad Aref Farooque, has been arrested, police said.
Farooque attacked his colleague Khanderay Solgir (40), attached to Nanalpeth police station, with a sword in full public view as soon as he came out of the police chowki this afternoon here in Central Maharashtra, they said.
Solgir, who suffered serious wounds, died on the spot.
Police said illicit relationship between Farooque's wife and the deceased led to the murder.