GURUGRAM: Three persons were arrested on Sunday from the Bangladesh border for the December 9 heist at the PC Jewellers store on Old Delhi Road. The arrested include an employee and two former employees of the jewellery store and police are looking for three more suspects.Six persons stole jewellery worth Rs 13 crore and 10 lakh from the PC Jewellers store last Sunday. Police have recovered most of the stolen items. The accused were part of a gang, which had been active for the past three years, and executed similar heists at jewellery stores in Delhi-NCR, Rohtak , Jaipur and Meerut.According to police, the accused who are all between 25-30 years are highly skilled in climbing building and cutting roof. They conducted extensive recce before striking, and in some cases, worked in a building to get an idea about its security system, internal structure and design. "Tech-savvy" and "sophisticated", they used to keep tabs on police investigations by checking local papers on the internet. After every crime, they crossed over to Bangladesh and returned to a different place in the country for the next crime. "They took months to plan any loot," said ACP (crime) Shamsher Singh.Zaffar Rehman (26), Saiful Mandal (26) and Sultan Mumtaz (26) are residents of Bangladesh and border areas of West Bengal. They joined the Sector 14 showroom of PC Jewellers on different dates in August and worked as helpers.