Investigators say the first two incidents incident happened Wednesday night when two boys, aged 13 and 10, showed up at a convenience store and a discount store.
The older boy concealed his identity and tried to rob the stores with bear spray, and the pair managed to get away with cash in one of the robberies.
The next night, the older boy broke into a locked grocery store and took money from the till.
A clerk who was there let her dog off its leash, and police say the boy discharged the bear spray at them, and then took off with cash.
Police say they tracked down the older boy, and then later found the younger one.
The 13-year-old faces numerous charges, but the 10-year-old is too young to be charged under the Youth Criminal Justice Act.