The tragedy happened after Zikhali arrived to pick up his girlfriend and saw the trainer behaving inappropriately with her.
Police say Zikhali left, then returned with a gun and opened fire, killing both victims. Emergency responders arrived quickly but could not save them. Zikhali was arrested and now faces two murder charges.
The gym is closed as the investigation continues. Locals are mourning and calling for peace and better ways to handle anger and relationship problems.