The incident happened at around 11:00 PM when the workers were operating at the workshop in Mukharjee Nagar area of North Delhi.
"Five armed men entered the unit and overpowered the employees working there, they then held them hostage and ransacked the workshop in search of cash, gold and other valuables. They stayed at the unit for around half-an-hour and then decamped with the booty," said a police official.
"We have questioned the workers of the jewellery workshop. Local CCTV footage is also being checked. Although we are investigating the case from all probable angles, the possibility of an insider being involved in the incident cannot be ruled out," the official added.