The victim, identified as Mustakeem was shot by Mukkaram, Jamal and Sartaj last evening in Civil Lines police station area over old enmity, they said.
According to police, the incident took placewhen Mustakeem was travelling on a motorcycle.
The victim died on the spot, police said, adding that he was brother of history sheeter Sonu Sakka who is presently in jail.
A case has been registered against the trio who are absconding, they said.
The body has been sent for postmortem, police added.