It happened just before 4 a.m. on July 5 at 7 Elements on 11th Street and Washington Avenue.
Police say there was an argument outside the club that escalated into a physical altercation involving knives.
At some point, a security guard, identified as 43-year-old Michael Welton, opened fire in an attempt to intervene, police said.
Welton was shot in the melee. Seven others were also injured in the shooting. All victims were reported to be in stable condition.
Welton was arrested and charged with attempted murder.
On Wednesday, police released a photo of a suspect allegedly involved in the incident.
Anyone with information is asked to call police at 215-686-TIPS.
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