Patna: The National Investigation Agency (NIA) on Monday formally took over the investigation of the case related to last month's bomb blast and recovery of two improvised explosive devices (IEDs) outside the Mahabodhi Mahavihara in Bodhgaya.

Inspector-general (Patna zone) Nayyar Hasnain Khan said all the documents related to the case lodged with the Bodhgaya police station in Gaya would be handed over to the NIA. Till date, the Gaya police were investigating the case.

The police investigation suggested the involvement of Jamaat-ul-Mujahideen Bangladesh (JMB) in the January 19 incident when spiritual guru the Dalai Lama was in Bodhgaya.

Khan said Gaya senior superintendent of police Garima Malik has received the requisition of NIA superintendent of police in this regard and the process to handover the case was underway.

The public prosecutor, special NIA court, Patna, Lallan Prasad Sinha, said the copy of the FIR lodged with the Bodhgaya police station has been submitted to the special NIA court. "The NIA has registered a case against unknown persons and started investigation," he said.

The development comes in the wake of interrogation of two JMB operatives from Bengal on Thursday. A Gaya police team interrogated the two arrested JMB operatives in Bengal on Monday.

A senior police officer said the NIA and the anti-terrorism squad of the state police were assisting the Gaya police in the investigation. However, the Gaya police in the case made no arrests. The video footage obtained from the CCTVs installed at the Mahabodhi Mahavihara had hinted at the involvement of four suspects.

The photographs of the suspects were also provided to different investigating agencies to ascertain their identities.