New Delhi, May 16 (PTI) The Delhi Police on Monday said it has so far collected biological samples of a total of 26 people, whose family members are believed to be killed in the fire at a building in outer Delhi"s Mundka, for DNA profiling.Preliminary investigation has suggested that various lapses, including lack of fire fighting equipment and blocked staircase, led to the tragedy, police said.At least 27 people were charred to death in the massive blaze that ripped through the four-storey building on Friday, according to the police."A total of 26 samples have been collected for DNA profiling, which will be carried out by forensic experts," a senior police officer said.The Delhi Police on Sunday had said it has collected biological samples of at least 20 people, whose family members are believed to be killed in the fire, for DNA profiling.These members also include kin of the eight people whose identities have already been ascertained, officials had said.A senior official said investigations into the incident has suggested that various lapses had triggered the fire.He said the building housed a warehouse in the basement where highly combustible items were stored.The staircase was blocked with batteries and inverters. There was only single entry and exit route, the official said, adding there were no fire-fighting systems working.The owner of the building, Manish Lakra, was arrested on Sunday, two days after the incident.The officer further said they are asking authorities, including the civic body, for providing documents for the investigation.Lakra was in the real estate business and had a shop on the ground floor of the building, police said, adding that his family is yet to be traced."We received information that Lakra was going towards Haridwar in Uttarakhand. We laid a trap and nabbed him from Ghevra Mod after conducting multiple raids in Delhi and Haryana,” Sameer Sharma, Deputy Commissioner of Police (Outer), had said on Sunday.Lakra used to live on the fourth floor of the commercial building. He lived in a two-room-kitchen house with his mother, wife and two children. He managed to escape to the adjacent building along with his family members when the fire broke out, police had earlier said.A CCTV camera and router manufacturing and assembling company, in whose office the fire is suspected to have started, had been on the premises since 2017. Its owners -- Harish and Vijay Goel, who are brothers, have already been arrested. PTI NIT TDS TDS TDS