“We can safely say it is about money… debt, money, payment, and so on,” Allaudeen said, adding that the bodies showed no signs of abuse or torture.

“They died from suffocation. We are still waiting for further reports from the relevant parties,” he said.

Allaudeen said four people detained in Petaling Jaya – three Sri Lankan men and a Pakistani man – on suspicion of harbouring the two prime suspects had been released and could be witnesses in a potential trial.

He said the five-room house was rented by a Sri Lankan couple in their 40s, their son who was in his 20s, and two other Sri Lankan nationals, aged between 20 and 30.

Police have confirmed the three who died were the tenants and the son. The parents were not home at the time of the incident.

Police believed there was a fight involving the two tenants.

On Sept 22, the same day as the murder, police detained eight people to facilitate investigations into the killing. The group included the two prime suspects, as well as the parents.

The father later died in custody on Sept 30.

“The investigation into the detainee’s death has also been handed over to the criminal investigation unit on deaths in custody under the Bukit Aman integrity and standards compliance department,” Allaudeen said, adding that it would not affect the case because the investigation papers were almost completed.