A gang allegedly broke into an office on the ground floor of a residential building in Salt Lake’s GC Block and fled with around ₹15-20 lakh cash on Wednesday night, police said.

A senior officer of Bidhannagar commissionerate said two policemen, who were on night patrol in the area, chased five men on two scooters without number plates.

But the gang members overpowered the two cops by brandishing a gun towards them.

CCTV footage in the area is being examined to identify them.

“We are inquiring about the exact sequence of events,” said a police officer.

The police said the burglars had broken the padlock on the main gate of the address and entered the ground floor of two-storey building whose owner is settled abroad.

The ground floor, which is leased to an egg distributor, has an egg-selling unit.

Sources said initially, there was no clarity on the amount of money that was allegedly stolen from the office. But later in the day, the figure was ascertained to be ₹15-20 lakh.

“We are probing all possible angles,” said an officer.

No one was arrested till Thursday evening.