The incident was reported on November 4.
It is suspected that one of the workers fed liquor and sweets laced with sedatives to his co-workers saying that it was his child's birthday, they said.
After the other workers lost consciousness, the accused fled with ornaments including gold and diamond jewellery, the police said.
By the time the incident took place, the jeweller, Kaushik Goswami, had gone home. He came to know about it the next day, they said.
During investigation, it was revealed that it was the missing worker who had stolen the valuables, they said, adding efforts are on to nab the accused.
Last month, valuables worth over Rs 14 crore were stolen from the workshops of two jewellers in the same area.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)