KOLKATA/MALDA: A mysterious drone appeared in front of Bengal CM Mamata Banerjee’s helicopter in Malda on Saturday just as she was heading to Gazole after a rally at Malatipur. Police have detained three people in this connection.Though the detainees claimed they had come to attend Banerjee’s rally and wanted to capture her boarding the helicopter, police are taking no chances.The drone was spotted by the CM herself. While boarding, she stopped on the helicopter’s stairs and looked into the sky for a while. “If the drone had hit the helicopter while it was trying to fly, it would have crashed. Police must find out who did this,” she said.When a helicopter is flying, it is the responsibility of air traffic control to keep the surrounding airspace clear. Airports Authority of India sources said no permission had been sought for operating the drone.Pilot Shubhagata Jowardar said it was not possible to predict the danger in such a situation. “It was an unauthorised drone. Though Malda airport does not have regular operations, there are severe restrictions wherever there is a CM’s movement,” an official said.