Four members of a family were found dead near Thodupuzha of Idukki district after their bodies were found buried in a pit near their house on Wednesday.
According to police, all the four had gone missing since Sunday and the decomposition of the bodies points to their death at least two days ago.
With neighbours noticing that there was no movement from the house, they informed the police who found blood stains inside, besides a knife and a hammer.
They then dug up pit near the shed behind the house where the bodies of Kanat Krishnankutty (60), wife Susheesla (50), daughter Arsha (21) and son Arjun (18) were found piled up one on another.
Residents said there was not much contact with the family who tried to remain isolated. Krishnankutty earlier ran a grocery store nearby and had a few rubber trees on his plot.
His daughter was doing her BEd course and son was a Grade XII student.
The mother and daughter had come to collect milk from a neighbour on Sunday. Since they did not turn for two consecutive days, neighbours informed their relatives and the police.
Local residents told police that they suspected that Krishnankutty was involved in witchcraft and people used to visit him at night.
Police ruled out theft as motive behind the murder and said investigation was on.