It happened around 1 a.m. Tuesday on the 5300 block of 5th Street in the city's Olney section.
Police say the male suspect, believed to be in his 20s, approached a 45-year-old man who was standing by an ATM inside the store. Within seconds, the customer is able to get a gun away from the suspect before shooting him several times.
"I heard two pops. I woke up out of my sleep and I heard somebody scream," said a neighbor who did not want to be identified.
The suspect fled the store and was later found dead inside a stolen car on the 400 block of West Olney Avenue, according to investigators.
At one point during the struggle with the suspect, police say a bullet hit a man who was waiting for the victim outside of the smoke shop. He is expected to survive his injuries.
The victim was not injured in the incident.
Residents in the neighborhood said they are fed up with the gun violence.
"Real scary for a person like me, an old man," said Juan Morales of Olney.
It's unclear if any charges would be filed in the case.
Police say the person who drove the suspect to the store is still being sought at this time.