It happened around 10 a.m. at the KNF Market on West 3rd Street.
Police say a male customer in his 20s was shot inside of the store. He was later pronounced dead at the scene.
Muhammad McBride, 18, was taken into custody around 6:30 p.m. Wednesday, according to investigators.
The identity of the victim is being withheld at this time until family members can be notified.
The motive for the shooting is still under investigation.
Anyone with information is asked to contact Chester Police Detective Stewart at 610-447-8429 or CID Detective Timothy Deery at 610-891-8030.
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