PATNA, June 12 -- At least 18 Bihar Special Auxiliary Police (BSAP) personnel were injured, 13 of them critically, after a sand-laden truck collided with a private bus carrying them on the Veer Kunwar Singh bridge in Bihar's Saran district on Wednesday morning, police said. The bus, with 45 BSAP personnel, was en route to Siwan from Dehri-on-Sone in Rohtas. The driver, Ramesh Kumar, had halted the bus on the Ganga river bridge on the left side due to technical glitches, when a speeding truck hit the bus from the front. Ramesh is critically injured, an officer said. The BSAP team was going to Siwan to prepare for PM Modi's scheduled visit to Siwan on June 20, Soni Kumari, one of the injured constables, said. Preliminary investigation revealed that the truck driver had lost control over the steering due to the high speed, as a result of which the truck crashed into the parked bus, superintendent of police (SP) of Saran Kumar Ashish said. The front portion of the bus was completely mangled, police said, adding that the truck driver fled the scene. Passersby and a police team from Doriganj rescued the trapped cops. Cranes and earth movers were used in the rescue operation. "We have registered an FIR under relevant sections of the Bharatiya Nyaya Sanhita, and efforts are ongoing to apprehend the driver responsible for the accident," the SP said. Those were grievously injured identified as Anirudh Kumar Pandey, Anita Kumari, Pramila Kumari, Puja Kumari, Dilip Kumar, Kanchan Kumari, Ayub Pradhan, Ranjana Kumari, Sunil Kumar Singh, Vakil Kumar, Amrita Kumari, Archana Kumari, Sushma Kumari, Sharmila Kumari and Sunil Kumar Rai....