While three bodies were found in a burnt state, another was cut into pieces and kept in a bag at the multi-storeyed house in the posh locality near Cliff House, the official residence of Chief Minister Pinarayi Vijayan and some of his cabinet colleagues.
The incident came to light after locals noticed thick smoke emanating from the house in the wee hours of the day and alerted the police.
Preliminary investigations revealed that it was a case of murder, police said adding the bodies were about three days old.
"Only a scientific probe would reveal further on the matter.
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Police have also received information about the accused," he said.
Police suspect the bodies to be of retired resident medical officer Jeen Padma, her husband Rajathankam, their daughter Caloline and a relative Lalitha.
The couple's son Kedal, said to be working in Australia and had recently come home, was missing after the incident.
Police have launched a manhunt for him.
Locals said the couple's daughter, pursuing her medical studies in China, had come home on a vacation recently.