MUMBAI, Dec. 6 -- A senior civic official has been arrested for the collapse of Ramabai Apartments in Virar East in August, the sixth arrest in the case. Gilson Gonsalves, assistant municipal commissioner in C ward, of the Vasai-Virar City Municipal Corporation (VVCMC), was arrested on Thursday, for failing to serve the contractor and owner of the property a notice even though he knew the building was riddled with irregularities and could pose a danger to its residents. Ramabai Apartments, a four-story building, collapsed on a rainy night on August 26, killing 17 people. Shahiraj Ranaware, senior police inspector with the Mira Bhayander-Vasai Virar (MBVV) crime branch, said that Gonsalves, during interrogation, was unable to explain why he had failed to serve the contractor and property owner a notice under the Maharashtra Regional and Town Planning Act, or take action for blatant irregularities in the structure. He has been arrested and remanded to police custody for five days. After the collapse, the Virar police registered a case against the contractor Nital Sane and land owner Parshuram Dalvi, who was deceased by then. Sane, who faces charges of culpable homicide amounting to murder, was arrested and is in judicial custody. As part of the investigation, a survey of the collapsed structure was conducted by the state government's public works department. It raised serious questions about procedural lapses and negligence in the municipal administration, leading to the calamity. According to the chargesheet, which has recorded the statements of 115 people, Sane had admitted that he and Dalvi, who had jointly executed the project, had not employed an architect. They had also converted 1-BHK apartments into 2-BHK flats, without expert advice. These flats were then sold to buyers. To establish that the building plan had been drawn up by an amateur, the crime branch asked the PWD to draw a plan of the collapsed building, based on revelations made by Sane, who had given them the floor plan. "The structure was 12 years old but, after examining the plan, we found that it was not strong enough to stand for even two years," said a PWD official. He said the structure was not built in the "legally correct way". "We have advised the police to get a structural engineer and a design engineer to record the exact flaws in the structure. However, in our opinion, the foundation dimension and scale design were not consistent with the structure's height," said the PWD official. "For instance, there was a mere 3-metre gap between the foundations of the two buildings, resulting in uneven settlement, due to which one entire section of the building collapsed," the official explained. Crime branch officers said Ramabai Apartments was built in 2012 and a structural audit was conducted by the VVCMC in 2018. Although the then assistant municipal commissioner, Subhash Jadhav, had found the building to be unauthorised, he had Merely issued a notice to Dalvi and Sane without registering a First Information Report (FIR). Neither did he evict the residents and demolish the structure, police said. Then, just four months before the collapse, assistant municipal commissioner Gilson Gonsalves conducted a structural audit of the building. But he too failed to take any action. "He issued a repair notice rather than moving to get the building demolished when it was obviously dangerous. Therefore, the names of both Gonsalves and Jadhav have been added to the chargesheet," said a crime branch officer. Police have also recorded the statements of former executive engineer Rajendra Lad and deputy engineer Eknath Thackeray, who were asked why a water connection was provided and house tax imposed on an unauthorised building. "Both said the municipal corporation had earlier decided to provide water connections to unauthorised constructions and impose house tax," said the crime branch officer. "They also said the assistant municipal commissioner was the sole authority who could take action against unauthorised buildings and they were just obeying orders....