Officers said the incident happened just before 10:30 p.m. February 28 at the store in the Timberlyne Shopping Center on Weaver Dairy Road.
Reports show the suspect grabbed cash from the register and fought with the clerk before leaving the store; the cash was later recovered.
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The suspect is described as a man in his 50s.
Those with any information are asked to call the Chapel Hill Police Department at (919) 968-2760, 911, or Crime Stoppers at (919) 942-7515.
Calls to Crime Stoppers are confidential and anonymous, and the caller may be eligible for a cash reward up to $2,000 for information that leads to arrest.