The Congress on Saturday said that it suspected Rakesh Singh, the alleged mastermind behind Friday’s attack on Bidhan Bhavan, was under the protective custody of an influential BJP leader.

Singh had led a group of BJP supporters who stormed the Bengal headquarters of the Congress in Calcutta on Friday and tore down and set fire to posters and banners of Rahul Gandhi, Priyanka Gandhi and Mallikarjun Kharge. The attack was organised in revenge for the alleged verbal abuse of Prime Minister Narendra Modi and his late mother during Rahul’s “Vote Adhikar Yatra” in Bihar’s Darbhanga.

“Police have arrested a few of those involved in the attack on our party office, an unprecedented culture of violence brought in by the BJP. Interestingly, the mastermind of the attack has remained at large even after 24 hours of the condemnable incident. So, we suspect he has been in the custody of an influential BJP leader, from where even the police have failed to arrest him,” said state Congress president Subhankar Sarkar.

“Even after doing such a crime, he had been chest-thumping on social media from a hidden shelter,” he added.

Three persons were arrested on Saturday for their alleged involvement in the vandalism of the Congress headquarters on CIT Road in Entally.

Bijay Prasad Dhanuk, 35, Santosh Kumar Rajbhar, 36, and Dibyendu Samanta, 43, were arrested from Kidderpore, Port area and Thakurpukur, respectively, in a case which was drawn up at the Entally police station on Friday after a senior Congress leader lodged an FIR.

The police said the three were charged with attempt to murder, mischief by injury, criminal trespassing, causing grievous hurt and mischief and under section of the Prevention of Insults to National Honour Act, 1971.

“We are trying to trace Rakesh Singh. A team had visited his house, but he wasn’t there,” a senior police officer said.

Congress leaders and workers took out a march in the city on Saturday to protest against the vandalism. The march started from the Congress’s headquarters and ended near the BJP office. The Congress units in various districts, including North 24-Parganas, Birbhum and Darjeeling, held similar marches.

Senior leader Adhir Ranjan Chowdhury took part in a protest rally organised by the state Youth Congress in Kidderpore.

“Our party workers wanted to take the protest up to the BJP headquarters to express their anger. But we did not allow it, as our party does not believe in the culture of violence, which is the BJP’s key weapon,” said Sarkar, the state Congress president.

Sarkar alleged that Singh was a close associate of the leader of the Opposition, Suvendu Adhikari.

“The leader of the Opposition in Bengal said he would be vocal for the people against Mamata Banerjee. Then my question is, what is the problem if Rahul Gandhi, who is the leader of the Opposition in Parliament, plays the same role?”

Asked about his association with Rakesh Singh, Adhikari said: “He is a BJP worker, and that is why he was present at different political programmes. Whatever our state president, Samik Bhattacharya, has said on this issue is also my opinion. The state president had said that the programme was not part of the party’s political agenda.

Bhattacharya had said that the party did not endorse the vandalism of Bidhan Bhavan.

BJP workers on Saturday took out a procession in Calcutta to condemn the alleged verbal abuse of Modi and his late mother.