An unidentified man on Thursday threatened to kill Bihar Chief Minister Nitish Kumar in a bomb blast, police said.
Patna Senior Superintendent of Police Vikas Vaibhab said a case was registered in this connection at a police station in Patna.
The unidentified man telephoned a few Hindi newspapers and TV channels, and told them that he would kill the Janata Dal-United leader by exploding a bomb.
The media outlets then informed police, the official said.
Police have launched an investigation, and are trying to track down the call and the man.