LONDON, April 10 (UPI) -- Drilling experts said the thieves behind a jewel heist at a London safe deposit building would have needed specialized equipment and a lot of time.
Investigators said the burglars broke into Hatton Garden Safe Deposit in London's jewelry quarter and accessed up to 70 safe deposit boxes, stealing an unspecified amount of jewelry.
At least one customer reported losing nearly $1.5 million in diamonds and other precious gems.
"Officers are working closely with Hatton Garden Safe Deposit Ltd to establish the identities of those affected," a police spokesman told the BBC. "Police will be contacting victims directly as and when they are identified."
Joel Vinsant, secretary of the Drilling and Sawing Association, said the thieves would have needed time and expensive equipment to get into the vault.
"It would take anything from 45 minutes to an hour-and-a-half -- it's 2 meters [6.5 feet] thick so they'd need specialist equipment," he told Sky News.
He said the thieves would have needed a large amount of water to keep the drill from overheating. "They'd have a lot to set up in terms of getting it under way," he said.
Vinsant demonstrated on video how the burglars may have used specialized equipment to get through a wall.
Diamond dealer Neil Duttson said it would be difficult to identify the stolen jewels.
"Once diamonds have been re-cut and polished there is no geological map," he said. "I imagine they will be sat on for six months. You can expect some cheap diamonds will be coming on the market soon."