The Bihar Police on Monday registered an FIR against members of the CBI team probing the Satyendra Dubey murder case on the complaint of father of one of the two persons, who allegedly committed suicide after interrogation by the agency, charging the CBI had poisoned them to death during questioning.

Police Superintendent Sanjay Singh told reporters in Patna that the police instituted the case on the complaint of Baijnath Sah, father of Sheonath Kumar Sah who along with Mukendra Paswan had allegedly committed suicide.

Baijnath charged the CBI with poisoning Sheonath and Paswan during interrogation, he said. An officer of the rank of Deputy Superintendent of Police, he added, was being asked to probe the allegation

"If necessary, we will seek sanction from the Centre for custodial interrogation or arrest of the CBI men probing the case," Singh said.

Sheonath Kumar Sah and Mukendra Paswan, who were grilled by the agency for several hours during the past few days, died after consuming pesticide at their native village Katari.

The police filed the case against the CBI officials without naming anyone under section 32 IPC (causing hurt by means of poison with intent to commit an offence) and section 302 IPC (murder), the SP said.