Police conducted a search operation in several areas of Orangi Town late night on Wednesday.
During the search operation, 18 suspects including a woman were taken into custody.
The geofencing of the incident has been done, and sketches of the attackers are being prepared with the help of CCTV footage.
An FIR for the Orangi Town firing incident was registered at the Pakistan Bazaar Police Station on Thursday.
The FIR includes murder and terrorism charges.