A 40-year-old man from Jagaddal in North 24-Parganas was arrested on Tuesday in connection with the alleged attack on police personnel during the Nabanna march on August 9.

Chandan Gupta was arrested at the Bentinck Street-BB Ganguly Street crossing for his alleged “direct involvement” in the assault. “Gupta has been arrested in connection with a case registered at New Market police station and charged under sections related to attempt to murder,” said Rupesh Kumar, joint commissioner (crime), Kolkata Police.

Sources said Gupta is known to be close to a senior BJP leader from Bhatpara.

“We supported the Nabanna Abhijan, but it was not an official party programme. Anyone who participateddid so individually. If the police have footage of someone assaulting officers, the law will take its course,” said Rahul Sinha, former BJP national secretary.

“But if they can arrest protesters based on video footage, when will they act against officers who mercilessly beat protesters?” he added.

Protesters in the August 9 rally, held to mark a year since the rape and murder of a junior doctor at RG Kar hospital, clashed with the police. Five police personnel were injured, including a security guard of the deputy commissioner (south suburban division), who suffered a critical head injury, an officer said.

A senior officer said Gupta was seen in video footage of the assault on the uniformed guard, who was pinneddown and beaten by a group of men.

The officer was rescued by his colleagues and was seen clutching his head even after getting back on his feet.

The police have filed five FIRs related to violence in different parts of the city during the rally.

The mother of the slain doctor, who suffered a forehead injury, lodged a separate complaint at New Market police station on Tuesday.