Progressive campaign worker fatally shoots colleague in heated argument.

A 46-year-old man was fatally shot by a fellow campaign staffer while handing out flyers for a progressive political group in Philadelphia ahead of the city's upcoming mayoral race. The two staffers reportedly had an argument on the street that quickly turned deadly when the 22-year-old drew his gun and shot the 46-year-old canvasser. Police are investigating the shooting and whether self-defense was involved. The alleged shooter, who at the time was legally carrying a firearm, was immediately taken in for questioning and has reportedly been fully cooperative with police. One PA, a progressive political group in Pennsylvania, confirmed the victim was one of its staffers.