A 22-year-old youth has been arrested in connection with the firing in the Ballygunge office of a coal merchant.
Police said Ravi Kumar Gupta, who was arrested on Wednesday, was a resident of Deoghar in Jharkhand and the “mastermind” behind the operation.
“He was standing outside that day, while two of his gang members entered the building. One of them opened fire in the air. Ravi Kumar Gupta is the main accused in the case,” said an officer in Lalbazar.
The two men had walked into a six-storey building on Sarat Bose Road, which houses the office of a coal trading company, and fired a bullet on January 8 afternoon. The bullet did not hit anyone.
Both have been arrested.
Gupta has been booked under IPC sections related to extortion and criminal conspiracy and also under the arms act.