The deceased was identified as M M Khan, an assistant legal advisor with the NDMC, police said.
The expertise with which the job was done, indicates the involvement of contract killers, a senior official said adding that police are investigating Khan's suspected rivalry with his relatives and some locals.
CCTV footage obtained from nearby areas are being monitored but the identity of the accused could not be ascertained yet.
The assailants on the bike were wearing helmets and shot at Khan from a close range.
Khan sustained a bullet injury in his chest and was rushed to a nearby hospital where he died.
Khan's relatives told police that he had been receiving calls from unknown people during odd hours of the day. Police have recovered his mobile phone and the call data will be analysed, the official said.