43 labourers died in the fire in Delhi's Anaj Mandi area early on Sunday morning
The Delhi Police's Crime Branch on Wednesday arrested the brother-in-law of the owner of the Anaj Mandi building, where a massive blaze claimed 43 lives, police said.
The building's owner Rehan and his manager Furkan were arrested on Sunday after the incident.
Police had said that during their interrogation, it was learnt that a portion of the building was owned by Rehan's brother-in-law Suhail.
Rehan also told police that a portion of the building was owned by his brother Imran.
It was found that there were 18 rooms which were let out, police said.
Suhail was arrested on Wednesday and raids are being conducted to arrest Imran, they said.
According to police, the site was visited by BSES officials and as well as a team of the Central Forensic Science Laboratory(CFSL).
Two buildings in the area were sealed and power supplies of the buildings, which come under the BSES Yamuna Power Limited, were disconnected, officials said.
Postmortem of all the 43 victims was completed and the bodies were handed over to their relatives.
According to police officials, a 3D laser scanning of the place of incident was done for the ground and first floors and the exercise is in progress. It is likely to be completed within two days.