A man and his younger son were found dead in a temple pond while the elder one's body was lying in the house with his throat slit, police said on Saturday.
The incident was reported at Navayikkulam near here.
The deceased was Safeer and his two sons aged 9 and 12, the police said.
Preliminary investigation revealed that the father had killed both his sons before himself, they said.
The killing and the suicide came to light after Safeer's auto-rickshaw was found parked adjacent to the temple pond near his house, they said.
"Both Sameer's and his younger son's bodies were fished out of the pond. The elder boy was found killed at their house, with the hands tied and the throat slit," a police official told PTI.
Safeer's wife was staying separately due to some family issues, the police said.
Though the children were staying with their mother, Safer had brought both of them with him some days ago.
"Before the killing, the father had taken the children to the beach and bought new dresses for them. We suspect he had been suffering from some mental problems," the officer said.
More details would emerge during the interrogation of wife and other family members, the police added.
