With the arrest of five people, the Kolkata police’s detective department on Tuesday claims to have solved a week-old Rs 1.3-crore robbery case.

The five had struck at a private consultancy firm where one of them worked. Police said nearly the entire amount was recovered from the residence of one of the accused on Monday morning.

The five were produced in a court today and were remanded in police custody for 14 days.

Police said the alleged mastermind, Anupam Dutta, worked with Pangene Biotech Private Limited at Fairlie Place, which deals in shares and real estate. He allegedly hatched the plot with one Sanjib Panja, who was fired from the company last month.

The kingpin then roped in his cousin Rajesh Pramanik, a drummer at a local bar Pink Room in Dacres Lane. Rajesh took along with him Swapan Chakraborty, a bouncer at the same bar.

A fifth associate, Mujibur Rehman, a daily wage labourer at a mill, joined them later. Except Mujibur, all the four hail from Kalna in Burdwan district and lived at Howrah and Belghoria.

Police said Dutta had been handling cash for the company and knew that every night, the firm’s 70-year-old owner Shyam Sunder Lahoti and his secretary Samir Manna count the bundle of the day’s transactions in cash. At that time, the office would be deserted. He also knew about the CCTVs that were recently installed in the office.

According to police, on January 13, the group of five reached the building with three plastic bags and an improvised pistol.

Dutta and Panja, who were known to the people in the office, hid nearby instructing the other three over cell phones. The three went over to the second-floor office, which was open.

The robbers first cut off the CCTV wires after which the man with the gun walked up to Lahoti and pointed it at his forehead while the others put a pad of cotton on Lahoti’s eyes and stuck it with plaster. Then, the robbers tied Lahoti and Manna. After putting the bundle of notes inside the bags, the trio fled.

The first complaint at Hare Street police station said the loot amount was Rs 30 lakh but it later put it at Rs 1.3 crore.

“The group most likely left in a bus, keeping the money with Rajesh who stays alone in a rented accommodation in Nilgunj Road in Belghoria. The pistol, too, has been found at his house,” said Police Commissioner Gautam Mohan Chakrabarty.

The first to fall in the police net was Dutta, a resident of Andul Road, who has been attending office regularly to avoid suspicion. “He was questioned and later confessed in the face of incriminating evidence,” said the police.

Police said Dutta and Panja used to handle Rs 20-50 lakh every day while their salary was Rs 3,000-Rs 4,000.