The Kanpur Police on Sunday formed a Special Investigation Team to inquire into the violence that took place on Friday over Bharatiya Janata Party national spokesperson’s comments about Prophet Muhammad, PTI reported.

A controversy had erupted after BJP spokesperson Nupur Sharma made the remarks during a show about the Gyanvapi mosque-Kashi Vishwanath temple dispute on Times Now on May 26. The party suspended her for “violating its constitution” on Sunday afternoon.

Videos on social media of Kanpur’s violence showed residents hurling stones at each other. At least 40 persons, including 20 police personnel, sustained injuries during the clashes, officials said. So far 29 persons have been arrested, PTI reported.

“All arrests so far have been made on the basis of photographic and video evidence from the scenes of riot with the help of human intelligence,” said Kanpur Police Commissioner Vijay Singh Meena.

A local court sent four persons to judicial custody, whom the police suspect to be the masterminds of the violence, The Indian Express reported on Monday.

The main accused persons have been identified as Hayat Jaffar Hashmi, Javed Ahmed Khan, Mohammad Rahil and Mohammad Suffian – all associated with a group called Maulana Ali Jauhar Fans Association.

Hashmi is the association’s national president, and has six cases pending against him, the police said.

“Documents related to the Social Democratic Party of India and the Campus Front of India were also found during searches at the premises of Hayat Zafar Hashmi,” Meena told PTI.

The Special Investigation Team has been asked to identify the instigators behind the violence, and whether they had any links with the Popular Front of India, which called for a closure of shops in Manipur and West Bengal, Meena added.

Meanwhile, the police on Monday registered a first information report at Kanpur Kotwali police station against 15 social media accounts on Facebook and Twitter, the Hindustan Times reported.

They were booked under Sections 505 (statements conducing to public mischief), 507 (criminal intimidation by an anonymous communication) and 66 (punishment for sending offence messages through computers) of the Information Technology Act.