Patna, Nov 21 : Three persons were killed and two others critically injured on Tuesday after a speeding car of Madhepura District Magistrate mowed them down in Bihar's Madhubani district, police said. The incident occurred on National Highway number 57 at 8 a.m., killing three people on the spot and critically injuring two others. After the accident, the vehicle rammed into the divider. The police are investigating whether Madhepura DM was inside the car at the time of accident or not. The injured were admitted to Darbhanga Medical College and Hospital (DMCH). The local villagers claimed that the victims were walking on the road when the speeding vehicle of Madhepura DM mowed them down. DSP of Phulparas and SDO reached the spot following the accident and took control of the situation. Following the accident, villagers have blocked the road, demanding action against the errant driver. They are also demanding service lanes on the stretch and compensation for the victims family. NH 57 connects Delhi to Silliguri via Lucknow, Gorakhpur, Darbhanga and Purnia. It is a four lane stretch but does not have a service lane. /IANS