Additional Director General of Police (Headquarters) Neelmani said that police officials have been asked to rush to Begusarai since the incident has sparked tension in the area.
Last year, Surajbhan Singh was convicted and sentenced to a life term for the Jan 16, 1992 murder of Rami Singh, a resident of Mathurpur village. Nago Singh, in his mid 70s, was the prime witness in the case.
Police sources in Begusarai said Nago Singh had received death threats before the pronouncement of judgement in the case in June 2008.
Surajbhan Singh is currently out of prison following the acceptance of his bail petition by the Patna High Court. He faces several criminal charges, including those of murder, extortion, kidnapping and looting.
Last year, he was accused of the murder of additional public prosecutor Ramnaresh Sharma, 55.