It happened at Verzenay Chicago on North Lincoln Avenue in the Wrightwood Neighbors neighborhood just after 9:30 a.m.
Video shows a masked person outside the bakery on a bike. They go through a backpack, appearing to have a tool.
Police said the thief broke into the front door, took money from the cash register, and then got away on that bicycle.
The bakery's owner believes the burglary was planned carefully, because there are typically people at the bakery during all hours of the day.
The owners said they have already replaced the broken door. Police have not made any arrests.
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