With meticulous planning and remarkable good fortune, the thieves who broke into a safe in London's diamond district seemed to have pulled off the perfect jewel heist. But their luck ran out on Tuesday when more than 200 Scotland Yard officers closed in on them.

Nine people were arrested in a triumph for embattled detectives whose early work had been criticized because of an embarrassing failure to respond to a midnight alarm at the start of a holiday weekend.

That delay gave the thieves more than 48 hours to carefully remove the contents of the safe used by jewelers in the Hatton Garden district.