Not much in the way of facts yet, other than the headline. The police say the shooter had a valid concealed carry permit and the robber was armed.
"A man on the scene shot the robbery suspect in the chest and abdomen, police said. It is not clear if the man was the owner, employee, or another customer."
Man with concealed carry permit shoots and kills robbery suspect inside Chicago cell phone store
Chicago armed robbery thwarted as gun owner with concealed-carry permit kills suspect: report | Fox News
"A man on the scene shot the robbery suspect in the chest and abdomen, police said. It is not clear if the man was the owner, employee, or another customer."
Man with concealed carry permit shoots and kills robbery suspect inside Chicago cell phone store
Chicago armed robbery thwarted as gun owner with concealed-carry permit kills suspect: report | Fox News