Patna, Oct 28 : A thief was killed and two others were critically injured after a violent mob nabbed and assaulted them brutally in Bihar's Samastipur district. The violent mob dunked the robbers' heads under water in a bid to kill them. The trio was identified as Vikas Kumar, Pinkesh Kumar and Ravi Kumar -- all natives of Nayaganj village under Deshri police station in Vaishali district. Some villagers made videos of brutal assault and shared it on social media. The incident occurred on Wednesday evening and one of the robbers died on Thursday evening. Om Prakash Arun, the DSP of Patori in Samastipur district, said: "The accused used to commit robberies at Dhamaun Chimni Vishar village in Samastipur district which is located on the border of Samastipur and Vaishali districts. Two brothers Santosh Kumar and Prem Kumar -- who are also the CSP operators of Inayatpur village -- had withdrawn Rs 1.5 lakh from SBI branch in Patori and were returning home. When they reached Dhamaun Chimni Vishar village, the robbers intercepted the siblings and tried to snatch the money. The victims raised an alarm and soon a large number of villagers assembled there. "The villagers chased the robber and the latter were firing on them. As the villagers were in large numbers, robbers in a bid to save their lives, jumped into a water pit. The villagers also jumped into it and brutally assaulted the accused using batons. They then dunk their heads into the water to drown them. On being informed, a police team headed by SHO Patori reached the spot and managed to rescue them," the DSP said. The critically injured robbers were rushed to a local hospital where Vikas Kumar succumbed to his injuries on Thursday evening. The condition of the other two accused Pinkesh and Ravi is also stated to be critical. "We have registered an FIR in this connection against unknown persons and tried to identify them through the video circulated on social media," the DSP said. /IANS