Greenwood Park Mall, Greenwood, Indiana
Apologies for the link to Fox, but it's the local news station for the area. Also, I'm linking to an early article that doesn't name the shooter. More updated info is available on later articles, and I'm not going to give a mass shooter any personal publicity.
Lots of commentary in the news/online on the rapid response of a private citizen, ending the assault prior to police or mall security arriving on the scene. Note that the mall had signage indicating a "no weapons" policy. Indiana state law does not give such signage force of law, so the armed "good Samaritan" was carrying his pistol legally. Also note that the citizen responder was not formally licensed: he was carrying legally under Indiana's constitutional carry law which took effect 1 July.
Should private citizens have the right to respond to active shooters with lethal force? Discuss.