Four men have been arrested for the assault on a police officer and the torching of a police vehicle on Rabindra Sarani during the BJP’s march to state secretariat Nabanna on Tuesday.

Two of the four are known functionaries of the BJP or its youth wing, relatives of the suspects and party sources said. The other two were identified as members of the party by police officers who spoke off the record. The four have been identified as Ravikant Singh, Sahil Roy, Anup Singh and Abhijit Roy. Ravikant, 35, had worked in the law cell of Calcutta police but quit to join the BJP as a full-time worker, his brother Sashikant told The Telegraph.

“He left his government job to join the BJP. He is a well-known leader now,” Sashikant said. A police officer claimed Ravikant was part of what the officer called the “action committee” of the BJP. Sahil, 22, is the president of the Bharatiya Janata Yuva Morcha’s Entally West Mandal, sources in the BJP said.

“He joined party politics after school. He never went to college…. He is the BJP leader here,” Sahil’s mother Simran Roy said. Assistant commissioner of police Debjit Chatterjee, who was chased and attacked with lathis by the mob, is admitted to SSKM hospital and will have to undergo surgery for a fracture.

Ravikant, Sahil and Anup have been charged with attempt to murder, deterring a public servant from performing duty and causing grievous hurt with dangerous weapons for the attack on Chatterjee. Abhijit has been booked under the prevention of damage to public property law.

The four suspects were produced before the additional chief metropolitan magistrate at Bankshal court on Wednesday and have been sent to police remand till September 20. BJP spokesperson Shamik Bhattacharya told this newspaper the party members had been framed by the police. “There was an unprovoked attack on our party members. They have been framed in these cases,” Bhattacharya said. Senior BJP leaders had earlier tried to blame the Trinamul Congress for the violence that left the ACP with a fractured arm, accusing the ruling party of infiltrating the march.

Ravikant’s brother Sashikant said Ravikant was picked up from an eatery at Tangra after he returned from the BJP programme on Tuesday. “He returned home in the evening after the Nabanna Abhiyan and left for Tangra to meet his friends. He was arrested at an eatery there. But we came to know about his arrest only in the morning when the police served us with his arrest memo,” Sashikant said at their Raja Rajendra Lal Mitra Road home on Wednesday.

Sahil is a resident of Shambhu Babu Lane in Entally. Sahil’s mother said five men came and arrested him from their home around 2.30am on Wednesday. Anup’s grandmother Shanti Devi said Anup was “innocent”. This newspaper could not contact Abhijit’s family at their Ashwini Nagar home in Baguiati.

Video footage of the violence circulating widely on social media shows Ravikant in a dark T-shirt running with a BJP flag in his hand, accompanying men who were chasing Chatterjee across Rabindra Sarani till the officer tripped and the attackers showered him with blows of lathis and kicks. When a group -– probably plainclothesmen –- tries to rush to the aid of the ACP, Ravikant is seen shielding the officer from the attackers.

Sources in the police said they had “enough evidence” to prove Ravikant was part of the mob that launched the attack on the cop with sticks. “He is a member of the BJP ‘action committee’,” an officer said. Another video of the march shows Sahil clapping with two slippers in his hands and walking on a central Calcutta road. Sahil had been arrested earlier as well for political violence, an officer said.

The police said they had identified at least 10 others who had assaulted Chatterjee and set a police vehicle on fire. Stills from video footage, in which the police have identified faces of some of those who were allegedly involved in the violence on Rabindra Sarani, were in circulation on Wednesday. “We are trying to arrest these people who were seen actively participating in the assault,” said a police officer at Lalbazar.

The officer added that footage capturing the assault on Chatterjee and the additional officer-in-charge of Jorabagan police station had been collected. A medical board has been formed at SSKM to review the assistant commissioner’s condition on Thursday and decide the date of surgery to insert a plate in his broken arm, an official at the hospital said.

The men who had assaulted the additional officer-in-charge of Jorabagan police station had yet to be identified till late on Wednesday evening. The police said nine others had been arrested in two separate cases — one under Hare Street police station and the other at Bowbazar police station — for hurling stones at cops and for damaging a police kiosk.

A fresh case has been registered against unknown persons at Jorasanko police station for allegedly throwing stones at the police near the state BJP office at Muralidhar Sen Lane on Wednesday evening.