A special squad claimed to have arrested the owner of the motorcycle, which was used in shooting dead a senior journalist.
The lawmen shifted the arrested to an undisclosed location for further interrogation. Raids to nail the culprits are underway.
Senior journalist Athar Mateen was shot dead in North Nazimabad when he was coming back after dropping her two daughters at school.
Reports said the deceased attempted to ran his car over two gunmen busy snatching a motorcycle from a citizen.
The gunmen started firing gunshots at him, killing him on the spot.
CCTV footage shows one of the shooters wearing a helmet and the other a cap and running along with the motorcycle.
The deceased was Tariq Mateen's younger brother.