A lawyer,who had filed a case against Lalu Prasad last year after a helicopter carrying the Railway minister landed on a national highway in Muzaffarpur district,today filed a murder case against the minister here for a bridge collapse. Sudhir Kumar Ojha,who is also a social activist,filed the case in the court of Chief Judicial Magistrate J K Sinha against Prasad for yesterday's collapse of a rail overbridge in this district headquarters town of north Bihar that left three dead. It was also filed against Executive Director of Ircon B P Singh,General Manager Gunasekharan,Deputy General Manager (Projects) Rakesh Roshan and Safety Supervisor Satya Narayan. In his complaint,Ojha alleged that the bridge was 'deliberately made to collapse just when he happened to pass over it' as part of a 'conspiracy' by Prasad and others as he had filed a case against the railway minister for having endangered human life by making an IAF chopper land on national highway during an aerial survey on August 1 last year during floods.