The man suspecting of murdering his parents, sister and aunt in their house in Thiruvananthapuram was arrested on Monday night, police said.
Kedal Jaison, 30. was held from the railway station on Monday night, police said, adding he was being interrogated and has admitted to committing the heinous crime.
The bodies of retired professor Raj Thankam, his wife Jean Padma — a retired medical superintendent of the General hospital, their daughter Carol — a medical student, and aunt Lalitha were found early on Sunday.
While three bodies were found in a charred condition, another mutilated body was found wrapped in a bag in their home, located a stone’s throw away from the residences of Chief Minister Pinarayi Vijayan and eight of his cabinet colleagues.
Police said the neighbours on late Saturday night saw smoke coming from the house and the fire brigade was alerted. It was only after the fire fighters came and doused the fire that they discovered the bodies. Police also said they had received information that someone was seen running away from the house on Saturday night and they believe that it was Jaison.
A relative of the family told media that Jaison had informed them that his parents have all gone for a tour and would not be back for a week.
Earlier in the day, the mortal remains of the deceased were interned at their family churchs’ cemetery.