A case has been started against a non-government organisation that had “summonsed” police commissioner Gautam Mohan Chakrabarti to a “mass trial” on alleged excesses by security forces.

Manabadhikar Suraksha Mancha (Masum) had organised a two-day convention in Moulali, which ended on Tuesday. As part of the convention, the NGO had organised a trial where 100 people, who allegedly suffered at the hands of police, BSF and CRPF, were supposed to narrate their plight.

The “summons”, which was sent to the Lalbazar headquarters of the city police, looked like a real court summons, said an officer.

The case against Masum director Kirity Roy was lodged under IPC sections 170 (personating a public servant), 229 (personating a juror or assessor) and 120B (hatching criminal conspiracy).

“We had asked them to clarify whether they are empowered to organise such trials, but they failed to satisfy us. So, we have started a case against the NGO,” said deputy commissioner (detective department) Jawed Shamim.

“The NGO members are neither government servants nor members of the judiciary. Still, they had asked people to come to the convention and narrate their grievances, promising to deliver them justice,” said an officer.

NGO director Roy said: “Let us see what happens. We had sent the letter to the police commissioner on May 23 but they filed the case on the last day of the convention. Why did they not react before?”

The NGO had also “summonsed” a few senior officers of the BSF and CRPF, but the central forces are yet to react.