Police: Armed bystander shot and killed Greenwood Park Mall shooter in just 15 seconds
https://www.wthr.com/article/news/local/multiple-victims-reported-in-shooting-at-greenwood-park-mall/531-df15bbf5-8eca-4220-b149-7de4735fbe37
"Greenwood PD said a review of surveillance video shows the suspect began firing at 5:56:48.
At 5:57:03 p.m., Elisjsha Dicken, an armed bystander, fired on the shooter from 40 yards away, according to police.
Within 15 seconds from when the shooting began, Dicken fired 10 rounds hitting the shooter as the shooter tried to retreat into the bathroom but collapsed and died.
An autopsy found the shooter was shot eight times and none were self-inflicted."
In addition, the article mentions how Mr. Dicken has no formal police or military training.