Surveillance cameras captured several angles of the incident back on November 30th inside Dean Food Market in the 1600 block of South Chadwick Street.
Police say the suspect was paying for his coffee when he began to argue about the price.
That's when he threw the coffee on the clerk and fled.
However, moments later, he returned with a knife and threatened the injured employee before leaving the store.
Anyone with information is asked to contact Philadelphia Police at 215-686-TIPS (8477), text a tip to PPD TIP (773847) or through PhillyPolice.com.
