The incident occurred around 9:30 p.m. on Dec. 9 at Bolds Pizza on the 1500 block of Spring Garden Street.
Police say three men had just robbed a CVS pharmacy at North Broad and Spring Garden streets when one of the suspects made his way into the pizza shop a block away.
Surveillance video obtained by WPVI-TV shows the would-be thief reaching over the counter as the clerk opened the cash register. A struggle ensues between the suspect and the clerk.
The video shows the teenager, who is the son of the pizza shop owner, pull out a gun and open fire, striking the suspect in the face. The suspect then flees the scene.
"There was money on the floor and there was also some broken glass inside the store, and there was also a large amount of blood," Philadelphia Police Chief Inspector Scott Small said last week.
Investigators say they followed a trail of blood down the stairs of a nearby subway station. Police say that's where they found the 33-year-old male suspect.
"From following the trail of blood, we also found some cash in the subway where the suspect was found," Small said.
The suspect was rushed to an area hospital where he was listed in critical condition.
According to police, surveillance video from the pharmacy matched the description of the injured suspect. Police are still looking for two suspects in connection with that crime.
The man who was shot has not been identified. No other injuries were reported.