A gang of thieves disguised as garbage collectors was caught on camera robbing millions of dollars in jewels in London's Diamond District. The Daily Mirror newspaper released dramatic surveillance footage of the high-profile heist, which happened Easter weekend and remains an open case.

The burglars are believed to have escaped with more than £60 million ($88 million) in jewels in one of Britain's biggest raids to date.

In two separate visits, six masked men entered Hatton Garden, the center of Britain's diamond trade, and worked through the night to crack open the vaults. They climbed down an elevator shaft and drilled through 6-foot-thick concrete walls, then stole the contents of 70 safe-deposit boxes filled with jewelry, Paul Johnson, detective chief inspector for London's Metropolitan Police, said in a statement.

The Met received a call April 3, which was Good Friday, and were told an intruder alarm had gone off the night before. Police decided not to respond, allowing the thieves to continue working through Easter Sunday and make off with jewels stored in plastic garbage bins, the footage shows. Officials are now investigating why police ignored the call, Johnson said.

The men apparently attempted to disable or remove surveillance cameras in the area to disguise their activities, but the Daily Mirror said the videos prove the team didn't do a thorough job. London detectives had separately obtained the footage before the newspaper published it, the Associated Press reported. On Saturday police released still images of what they called three "highly audacious" suspects.

The Daily Mirror named the robbers, whose real names are unknown to the public, Mr. Ginger, Mr. Strong, Mr. Montana, the Gent, the Tall Man and the Old Man. The newspaper said it is feared the gang has already fled the country.

"This was clearly the work of a professional gang who planned this job down to every last detail," a source told the Daily Mirror. "But they may have made a mistake in leaving this footage behind."

Hatton Garden has been the victim of other big-ticket robberies, the AP noted. In 1987, two armed thieves stole an estimated $90 million in jewels, while in 1993, robbers handcuffed shop workers, smashed through high-security doors and busted a safe to steal millions of dollars in diamonds.