PATNA: Indian police said Thursday a domestic militant group called the Indian Mujahideen was behind deadly bomb blasts at a rally by radical opposition prime ministerial candidate Narendra Modi.

Police have filed an initial case against the outfit and five of its operatives over the string of blasts which killed six people last month at the rally in the eastern city of Patna, shortly before Hindu hardliner Modi took to the stage.

“An FIR (first information report) has been registered at the Gandhi Maidan police station in which many of its top operatives... were booked,” senior police official Ravinder Kumar told AFP from Patna.

The report is a first step toward formal charges against the group, which has links to militants in Pakistan and has been accused of a number of deadly attacks in Indian cities in recent years.

Modi is a divisive leader of the main opposition Bharatiya Janata Party and is despised by Muslims as he is widely held responsible for 2002 communal riots in the western state of Gujarat, in which up to 2,000 people, mainly Muslims, had died.

Six people were killed and dozens injured in the blasts on Oct. 27 as tens of thousands gathered to hear Modi speak. One of the bombers also blew himself up while trying to evade arrest.

Modi and rival Rahul Gandhi from the ruling Congress party are holding a series of mass rallies across the country in a battle to win five state elections by year’s end. The elections are seen as a bellwether before a general election in 2014.

The five operatives suspected of being behind the blasts include Yasin Bhatkal, one of India’s most wanted men and a co-founder of the extremist group who was arrested in August.

According to Patna police, filing the case will allow its officers to question Bhatka, who is in detention and has been interrogated by the National Investigation Agency.

Last week the NIA, which is also probing the rally blasts, released sketches of five suspects, other than Bhatkal, and offered a cash reward for any information about them.