Kolkata: Police arrested a sub-assistant engineer of Kolkata Municipal Corporation (KMC) in connection with the collapse of an under-construction three-storey warehouse in Taratala, killing 16 people this June.Aminur Sheikh (28) was arrested from his residence in Bansdroni on the southern outskirts of Kolkata on Saturday morning, a police officer said. However, the arrest led to unrest among the civic body’s sub-assistant engineers across departments. These engineers from different boroughs gathered at KMC headquarters and demonstrated against the civic body’s inaction in offering legal protection to the arrested engineer who, they alleged, had been made a scapegoat.The agitating engineers entered the chamber of the director-general (building) to hand over a list of demands but in the absence of the DG, they interacted with other senior officials. According to a sub-assistant engineer who was present at KMC headquarters, they would be compelled to go for a cease-work if the civic authorities failed to ensure justice for the arrested sub-assistant engineer who had hardly any role in the entire ‘episode’ that led to the collapse of the warehouse. “He happened to be one of the signatories to the sanctioned plan. But there were others who were much above his rank and influential. Have cops initiated any action against them?” asked a sub-assistant engineer requesting anonymity.With Sheikh’s arrest, the number of people arrested in connection with the collapse has risen to seven.According to a police officer, Sheikh was in charge of the construction in ward 80 under KMC. His role in the approval of the construction and related documents is now being examined, while cops are also trying to ascertain who else was involved in the process.Structural experts from Jadavpur University were also involved in the probe as authorities examined the possible technical and procedural lapses that led to the collapse.The incident had raised questions over KMC’s construction approval and inspection mechanisms, with investigators now focusing on the roles of officials, contractors and others associated with the project. The findings could determine responsibility for the fatal construction failure.