Seven persons were arrested in connection with violence that had rocked Sujapur under Kaliachak police station of the district during the nationwide strike by trade unions on Wednesday.

Some others have been detained and police are trying to find out whether they were also involved in the violence and the attack on policemen. The arrested seven were produced in a court here on Thursday and remanded in police custody.

Alok Rajoria, the superintendent of police of Malda, said: “Seven persons have been arrested. We will strictly deal with vandals. Investigation is in progress to trace others involved in the violence.”

Told about a video that showed some suspected policemen damaging windscreens of vehicles with butts of firearms at Sujapur, Rajoria said: “If anybody is found involved in such things, necessary steps would be taken.”

Isha Khan Choudhury, the Congress MLA of Sujapur, slammed the police for the arrests.

“People should not be harassed and arrested as they had protested against the CAA and NRC. They didn’t say anything against the state government. We fail to understand why police arrested people.”