Lalbagh police busted a mugging gang that has been robbing people while disguised as detective branch police or Rab for the last eight years.
They targeted people who would withdraw large amounts from bank or other financial institutions.
Before every operation, all gang members managed new SIMs and used Mobile Number Portability (MNP) service that allows subscribers to swap networks without changing their existing 11-digit number.
Using the MNP, they would register their SIM to other operators and made calls to exchange their internal communications during any criminal operations.
This way, the operator cannot provide law enforcers with call detail record (CDR), last call location and other information, said an officer of Lalbagh Division of Dhaka Metropolitan Police (DMP) yesterday.
"It confused the investigators," he told The Daily Star, seeking anonymity.
Police uncovered the details on the gang of 17 while investigating a case filed in connection with the criminals mugging Tk 3.20 lakh from the manager of a plastic factory from Azimpur area on January 12 after he withdrew the money from a bank in the area.
"We have already arrested six members of the gang including its ring leader on different times from different parts of Bangladesh," Biplob Bijoy Talukder, deputy commissioner of Lalbagh Division of DMP said yesterday.
Police seized three jackets similar to that of Rab, a plastic toy pistol, several SIMs, a Swiss gear knife, two private cars used for snatching, fake NIDs and some cash. Police are trying to seize another private car they use in operation.
The arrestees are ring leader Biplob alias Shyamol; Imran Hossain; Md Ali Bullet and his brother Ahmed Ali Rubel; Jahangir Alam and Al Amin.
Another accused Md Momin was also directly involved in robbing the plastic factory manager. He is on the run. Of those arrested, Imran confessed to his involvement before a magistrate recently, the DC said. One of their members would locate a target withdrawing cash and follow the person after they came out of the bank.
He would then inform the other gang members, who would intercept the target, introducing themselves as law enforcers. They would then blindfold and forcefully take the "target" away in their car.