The arrested individuals have been identified as Manish Lakra -- the owner of the building, and Harish Goel and Varun Goel -- owners of a firm named Cofe Impax Pvt Ltd., the police said on Sunday.
So far, only eight of the 27 bodies have been identified.
The eight deceased have been identified as Tania Bhushan, Mohini Pal, Yashoda Devi, Ranju Devi, Vishal, Drishti, Kailash Jyani and Amit Jyani.
Officials said that most of the bodies were burnt to such an extent that even it was difficult to establish whether the charred remains were of a man or a woman.
However, two days after the incident, the medics have now found that of the 27 dead, 14 are females and three males.
The unidentified bodies have been placed in the Sanjay Gandhi Memorial Hospital's Mortuary here in Mangolpuri.
"We have collected the DNA samples of the rest of the bodies. As soon as DNA matching is completed, we will get to know their identities," Deputy Commissioner of Police Sameer Sharma said, adding it might take 4-5 days more.
Both Harish Goel and Varun Goel were arrested a day after the incident but the owner of the building Manish Lakra was absconding.
Subsequently, a police team was constituted which tracked his locations, and Lakra was arrested from Ghevra Mod in west Delhi, near the Haryana-Delhi border.
During the preliminary enquiry, it was revealed that Lakra was present at his residence on the top floor at the time of the incident.