The CID on Friday submitted a chargesheet naming Trinamul councillor Mohammad “Munna” Iqbal as the mastermind in police officer Tapas Chowdhury’s murder, its case against him built around 122 witness accounts.

Sources said the chargesheet gives a blow-by-blow account of the incident at Garden Reach on February 12, also describing how the face of Trinamul in the port area allegedly instigated a group of young men who had screamed “maro… maro” and run towards where the victim was standing.

An ABP Ananda cameraman had captured on video one of those men taking aim and firing at sub-inspector Chowdhury with his gun in the melee over student union elections at Harimohan Ghose College. Prime accused Munna went into hiding the same day.

The chargesheet, submitted in Alipore court, comes 57 days after the police arrested Munna at Dehri-on-Sone railway station in Bihar.

The councillor’s family has challenged the CID to prove the murder charge in court. “My father is innocent. The CID may have filed charges against him but I am confident they will not be able to prove them in court because everyone knows that somebody else has committed the murder,” his daughter Saba told Metro on Friday.

A source close to the family said the CID’s “flimsy” chargesheet could help rather than harm Munna’s cause. “This will make his acquittal easier. TV footage has shown someone else firing the shot, and no weapon was found on him…. He will come out of jail as the CID’s findings get trashed in court.”

The investigating agency insisted it had strong evidence against Munna. “Eyewitness statements are considered prime evidence during trial. A murderer need not always kill the victim. The link between the killer and the person who executes his decision is the key,” an officer said.

A colleague of the officer cited the American Center attack to drive home the point. “Five policemen were killed and 20 others were injured in the American Center attack in 2002. The court sentenced Aftab Ansari, the mastermind, to death despite him not even being in India when the incident occurred,” he said.

The chargesheet cites depositions by 122 witnesses. “Apart from Mohammad Iqbal, Sheikh Subhan, Ibne Saud and Mohammad Imtiaz, we have mentioned five others in the chargesheet who are still on the run,” said a CID officer. “We have slapped stringent sections of the IPC, including murder and attempt to murder, on all the accused. They have also been charged under the arms act,” the officer said.

Quoting from the chargesheet, another officer said hitman Subhan and others ran towards Chowdhury after Munna instigated them. “Subhan took out a firearm and pulled the trigger, targeting Chowdhury as he was trying to separate a youth whom Munna’s men were trying to drag away,” he added.

Subhan, his uncle Saud and Imtiaz are all known to be close to Munna.

Trinamul minister Firhad Hakim had publicly backed Munna after the incident, claiming that the councillor was the target of the attack rather than the conspirator.

Pressure mounted on Munna after TV footage proved his presence in the area and showed the hand of his aides in the attack. The Trinamul leadership then tried to distance itself from the dramatis personae, while Hakim claimed he was unaware of the “real situation” when he gave his reaction.

“The murder charge has proved that the ruling party gave the police a free hand,” a police officer not associated with the probe said on Friday.

Munna had been on the run for 23 days after the incident at Garden Reach, allegedly with the assistance of a section of Trinamul leaders. His arrest in Bihar on March 7 came amid speculation that he was under pressure to surrender.

The detective department of Calcutta police was in charge of the Garden Reach probe until the government brought in the CID.