The motorcycle-borne gunmen stopped a three-wheeler at a gunpoint and snatched a bag containing the ornaments from the jeweller Manohar Verma (50) before shooting him to death after he tried to raise an alarm, Superintendent of Police (SP) P Kannan said.
The slain jeweller was riding a three-wheeler on way to a destination in the town to deliver ornaments to a client, he said, adding that the criminals had prior information about movement of the deceased.
A case has been registered in connection with murder of the jeweller and loot of ornaments from him, Kannan said, adding raids were being carried out to nab the culprits.
The body has been sent for post-mortem, he said.