What was first thought to be a "booby trap" was actually just a byproduct of one angler's spirited fight against a large fish. After a bicyclist crashed along the Denver stretch of the Platte River, it was originally thought that a clothesline was set up to purposely hurt those riding on the trail.
But it was soon learned that the first person to discover him, a man fly-fishing, was also in the midst of a fight with a large fish and as the bicyclist's head grazed the line, he lost control. Sounds like quite a fish.