Bala Raju (42), who was on duty near Mahankali temple, consumed the pesticide after mixing it in cold drinks and died, Inspector Satyanarayana said.
"The victim, who was attached to Mahankali police station, had a marital dispute and it seems he took the extreme step owing to this problem," he said.
Local news channels aired a footage, in which Raju could be seen mixing something in a cold drink bottle, before consuming its contents.
A case has been registered in this connection and further investigation is on.