Pittsburgh Police officers from Zone 5 responded to the Family Dollar on the 8100 block of Frankstown Avenue for an armed robbery in progress at 7:10 p.m.
When officers arrived on scene the male suspect had already fled on foot.
Officers spoke with three witnesses who told them an unknown male entered the store, immediately approached the counter and pointed a firearm at them, demanding money from the register.
The male then fired a shot into the wall past the employees before taking an undisclosed amount of cash from the register and running out of the store.
No one was seriously injured.
The Mobile Crime Unit processed the scene.
Robbery Unit detectives are investigating.