The Supreme Court on Thursday asked the Central Bureau of Investigation to inquire how Member of Parliament Rajesh Ranjan, alias Pappu Yadav, could throw a party in Patna's Beur jail.
The CBI has till December 13 to submit a report to the court.
The Rashtriya Janata Dal leader is in jail in judicial custody after being named as an accused in the murder of Communist Party of India-Marxist legislator Ajit Sarkar in 1998.
The Indian Express newspaper quoted Inspector General, Prisons, Deepak Kumar as saying that he came across Yadav hosting a gathering of more than 50 supporters, in violation of the jail manual.
The gathering, the paper quoted sources as saying, was being held in an area where even visitors with permission are not allowed.
The jail authorities, in fact, provided all facilities for the meeting.
Barely a month ago the Patna high court had ordered a first information report to be filed against Yadav for throwing a party in the jail.