Rappelers Death in East Zion 9/4/2017

A fellow died 9/4/2017 while canyoneering in east Zion.
My mom's cousin, a doctor, and his sone, were at a near by rappel and  were the first to respond to the individual. The man was wearing a go-pro, and so the cause has become quite clear. As far as I know it hasn't made public news- but that's fairly common.
As always please treat the families and individuals with respect. I share this to help prevent further harm to other individuals. I don't know anything about that parties skill levels (or my mom's cousin for that matter), but when describing it to me it made very clear sense.

The fellow had been rapping down a fairly large rap. About 80 ft from the bottom he had to adjust something. Instead of his free hand, he took his break hand off the line. There was no fireman. He started dropping, and couldn't regain control. He smashed into rocks multiple times on his way down. He died from internal bleeding, though it was clear that he suffered brain trauma as well.

Cautious confidence preserves, cocky kills. I am not trying to imply this man was cocky, simply that he did not take easy precautions.
I don't know if there was a stop knot at the bottom, but it wouldn't have mattered- it was the way down, not the stop, that killed him. He was the first down so there was no fireman.     A prussik beneath the rappeler, binered to a leg strap, prevents, or at least slows, unintentional break loss. You never know when your hand is going to smack a rock and cause the fling back reaction of release. Rope burn and pinching are always a potential.   Also, my mother mentioned that it was a thin diameter rope- this might have been problematic as well.

Please folks, lets remember to respect the wild, so we can be the wild.
Stay safe, and Rock On.

My prayers go to the family. 

It was in the news: http://www.sltrib.com/news/2017/09/04/man-dies-while-rappelling-near-zion-national-park/

Sounds like a fundamental error - releasing the brake hand.