RAB-3 said it detained three men in separate operations in Malibagh and Khilgaon on 3 August.
The force identified the detainees as Mohammad Swadhin Ahmed Rony, 35, Mohammad Sajjad Hossain Sohel, 30, and Mohammad Mehedi Hasan, 24.
RAB-3 said three 7.65mm pistols, five magazines and 38 rounds of ammunition were recovered from the homes of Sohel and Mehedi.
It said officers recovered three walkie-talkies, two chargers, a Chinese axe, a machete and a switchgear from Rony’s rented home.
RAB-3 alleged that the three men were associates of the Zisan group, which it said was active in Khilgaon, Goran and Malibagh.
The force alleged that they used walkie-talkies instead of mobile phones to communicate while carrying out extortion and other criminal activity.
RAB-3 further alleged that the detainees threatened owners and contractors at construction sites to demand large sums of money.
The supplied evidence does not establish the allegations independently or state the outcome of any court proceedings.