In four minutes or so, they're done, the FBI and local police officials said.
''This isn't luck. You don't do 56 robberies without being caught," FBI assistant director Chris Swecker said. Investigators said the crew almost certainly is responsible for 51 burglaries in 10 eastern states and may be involved in cases in Florida and Illinois.
Their most recent heist was Wednesday at a Zales Jewelers in Bay Shore, N.Y., FBI officials said.
The value of their take has ranged from $7,500 in Colonial Heights, Va., in April to more than $260,000 in suburban Baltimore in August 2003.
The FBI is investigating five Connecticut heists involving more than $487,000 worth of jewelry. Shopping malls in Waterford, Milford, Manchester, and Enfield were robbed between December 2003 and last May.
''They actually cut the gates and went through the stores, taking whatever was there," said Enfield Deputy Police Chief Carl Sferrazza, describing burglaries at two jewelers at the Westfield Shoppingtown mall on the same night in May. Police estimated the losses at $100,000.
The items taken have no serial numbers, making them nearly impossible to trace, Swecker said. But he said one important clue may be the predilection for Movado watches.
FBI Special Agent Kevin Hennessy, an investigator based in Albany, N.Y., called Movado ''the poor man's Rolex," noting that it bears no serial number and might be resold for $500. Hennessy said the other jewelry could be melted down.
The FBI has set up a telephone hot line, 800-225-5324, and is offering a $25,000 reward. Jewelers are offering another $25,000, said John Kennedy of the Jewelers Security Alliance, an industry association.
The core group of thieves numbers four to five men, although some break-ins involved up to six people, investigators said. Hennessy said the group has ties to New York City and that the FBI has recovered some fingerprints and identified possible suspects.
The thieves appear to focus on stores in malls, which are just off major roadways and allow a quick exit. The crew does extensive surveillance before the crime, sometimes slashing the tires on mall security vehicles or putting glue in the locks, Swecker said.
At least one person stands lookout while several enter the store and fill bags. They ignore store safes and women's jewelry, he said.
A typical break-in took place in October, when a six-person crew used a battery-powered saw to cut the gate at the Zales store inside the Willow Grove Park Mall in Abington Township, Pa., at 10:50 p.m., according to the local police. The thieves cut power to the store, knocking out surveillance cameras, the police said.
Besides the burlaries in Massachusetts, Maryland, Virginia, Connecticut, Pennsylvania, and New York, the FBI blamed the group for thefts in Georgia, New Hampshire, North Carolina, and Rhode Island.
