I know exactly where this is, I’ve driven by it dozens of times. It’s a riverbank park right near downtown shreveport, popular with joggers, bikers, etc. The temp has been over 100 degrees for several days. The river is low and must have looked deceptively placid and inviting.
I lost an uncle to the Kern river, I saved my brother from a river, and I have had a couple of close calls on rivers and in bayous.
Ronald Reagan was the most successful river lifeguard in his region, I think that he was credited with almost 100 saves, including one when he returned to the river many years after leaving that work.
From a source I know in the area, it is said that one of the teens stepped on a large snapping turtle which sparked a panic and led to them charging into the deeper water.