Mumbai: Mankhurd police on Monday arrested the contractor and owner of the unauthorised ground-plus-three-storey slum tenement that collapsed onto an adjoining ground-floor shanty at Janata Nagar in Mandala area on Sunday night, killing five children and a woman and injuring a man.Based on a complaint lodged by Mohammad Mukhtar Abdul Ali Shaikh (53), police registered an FIR under BNS sections 105 (culpable homicide not amounting to murder) and 3(5) (multiple individuals act together with a shared intention to commit an offence) against Abdul Wahid and Gulam Raza Sayyed. The duo was produced in court and remanded to police custody.Moinuddin Shah (39), who lost his entire family — wife Akhtar Jahan (38) and children Kaisar (14), Jalaluddin (9), Serajuddin (7) and Anabiya (3) — in the tragedy, said he was to shift to a new place on Monday as he had noticed that the ill-fated structure, located two shanties away from his hutment, had begun tilting. “I told my wife to cook dinner and within 10 minutes of me stepping out around 8.30pm, this happened. I had told my children that we will somehow manage to sleep here for a day and vacate the house tomorrow [Monday],” Shah, a labourer by profession, told neighbours.Neighbours said his children studied at a municipal school, and his eldest, Kaisar, was a bright student.Six-year-old Aliya Shaikh, who had come to play with Shah’s children, was also killed in the crash. Aliya’s father Allauddin Shaikh, who works for a cargo company, said she had started Class 1 only last month. Both the Shahs and Shaikhs are originally from Uttar Pradesh.The only survivor of the incident, 24-year-old Rehan Ali, who sustained a fracture to his hand, is recovering in hospital. He said he lived on the ground floor of the ground-plus-three-storey slum tenement that collapsed onto the Shahs’ shanty. On Sunday morning, his family had noticed cracks developing in the building and had begun vacating it. Ali had briefly gone back inside to retrieve one last bag and had just stepped out when the structure came crashing down.While the structures stood on govt land, revenue officials said they are predated 2011 and had been surveyed by the Slum Rehabilitation Authority, with the settlement assigned a cluster number. They said residents could not be relocated, unless they were rehabilitated. However, BMC officials said they had warned revenue authorities about unauthorised construction on the marshy land. “We had told them to carry out a drive against the illegal construction and that we would help them with it. Even if they are prior to 2011, they cannot construct beyond 14 ft height. However, a large number of structures were built beyond the permissible limit. Even the structure that collapsed was built about three years ago,” a BMC official said.On Monday, chief minister Devendra Fadnavis announced an ex gratia of Rs 5 lakh each for the kin of the deceased, while the BMC demolished a dangerous structure adjacent to the collapse site and cleared the debris.(With inputs from Ahmed Ali)