Chandrika Rai, the DIG of Kosi received the call on June 24 and an FIR was registered in this regard, Superintendent of Police Ashwani Kumar told reporters here.
Identifying himself as Azam Khan of Uttar Pradesh, the caller asked Rai to shell out Rs 20 lakh for his own safety, he said.
The DIG had drawn the attention of Darbhanga Inspector General of Police Umashankar Sudhansu into the matter, who ordered the lodging of FIR at Sadar police station in Saharsa, Kumar said.