Teenager in custody after gunshot fired inside Philadelphia mall, police say

Authorities say a teenage boy is in custody after an argument lead to a gunshot being fired inside a busy Philadelphia outlet mall on Tuesday night.

Police responded to the Fashion District on 9th and Market street around 6:30 p.m. after an officer reported hearing a gunshot. 

Inspector D.F. Pace told reporters a nearly full ammo magazine from a semi-automatic handgun fell out of the suspects gun, preventing further shots. 

"The magazine somehow fell out of the gun and the shooter was unable to fire any further," Pace said. 

Authorities report that one man suffered a minor shrapnel injury after a bullet ricochet off a granite wall. 

Police are using surveillance footage to discover a possible motive.