Customer sees another customer enter Walmart with concealed weapon. First customer follows him into store, comes up behind him and puts him into choke hold.
http://www.wtsp.com/story/news/local/2015/01/20/shopper-tackles-man-with-gun-at-wal-mart/22067325/
http://www.wtsp.com/story/news/local/2015/01/20/shopper-tackles-man-with-gun-at-wal-mart/22067325/