The incident took place yesterday when Krishnapal Singh, who also owned a photostat shop outside a local court here, was returning home after work.
Some bike-borne miscreants fired bullets on the way, they said. A passerby also received minor injuries in the shooting.
According to police, Krishnapal's sister Rita and brother-in-law Arvind were murdered in 2001 and he was the lawyer of the case.
Police said they suspect that this could be the reason behind Krishnapal's murder.
He said the lawyers have submitted a memorandum to the District SSP regarding immediate arrest of the killers.
Police have registered a case against four unknown persons and a search for them is on.