Three fresh arrests have been made in connection with a robbery on May 5, where two employees of a forex company were robbed of ₹2.66 crore that they were going to deposit in a bank. The arrests were made on Wednesday night.

The accused includes a “source” of a Kolkata Police constable arrested in the case on Tuesday.

An internal inquiry has been initiated in the Special Task Force (STF) of Kolkata Police to ascertain how STF constable Mintu Sarkar obtained the tower location details of the forex company employees transporting the cash on the day of the robbery.

According to sources, based on Sarkar’s statements, police zeroed in on Sahanaj Sheikh alias Raju, from whom police seized ₹31.5 lakh. The cash was recovered from Raju’s home at Mandirbazar in South 24-Parganas on Thursday morning.

The other two persons arrested on Wednesday night have been identified as Nazmul Hussain of South 24-Parganas and Sheikh Rahamat of Entally.

Police sources said Sarkar had obtained information about the movement of the high-value cash from his source Raju, who had received the information from one of the forex company employees. This employee has already been arrested.

The fact that several tower location details of the two men who were transporting the cash were found with Sarkar, had become a cause of “concern” for the city police, an officer said.

“The Special Task Force is a sensitive unit. It is of deep concern if an STF officer who is not entitled to collect any tower locations is found to have tower location details of civilians who are neither accused nor suspects in any case,” said an officer.

Sources said an inquiry has been launched to find out Sarkar’s source.

On the afternoon of May 5, two employees of a forex company in Taltala were robbed of the money that they were going to deposit in the bank.

Two men had intercepted the taxi they were travelling in at the Phillips crossing and barged into the vehicle. They took the cab to Kamardanganear Topsia, where two other men appeared and fled with cash.

Police later arrested one of the company employees who knew about the cash transfer.