UPDATE - Police say it was an accident with fisherman not a "Booby Trap"

From 9News

Last Friday night around 6:30, a 62-year-old bicyclist had his ride end abruptly when he was clothes lined by fishing line stretched across the path.
"We asked the trauma room and they said that when the EMTs brought him in that he had had a clothes line accident and they kept saying that there was fishing line pulled across the bike path and that he ran into it," the victim's wife said. "He said there was an eyewitness and he flew off his bike forward, landed on his head and rolled and that they called it a booby trap."

News Item: 


This trail is NOT dangerous

This trail is NOT dangerous considering thousands of cyclists use it and cases like yours and this happen rarely. Your story is suspect anyways, sorry, but if you're going to scare people then you need to provide some evidence. I personally have ridden is exact spot maybe, I don't know, 500 times with no issues. You will definitely see homeless people near the paths, many of them are mentally ill, but harmless. Kids did this and like Kris said Denver police need to investigate. There are hundreds of kids in the apartment complex near by and they could start there.

I can think of at least three

I can think of at least three scenarios where you would fall forward. The fishing line could have been could have been placed very low and caused an endo. Or hitting the line might have thrown off his balance and he tried to recover and over compensated. Or maybe he saw the line at the last moment and had to emergency brake and locked up his front wheel.

If a fishing line was strung up intentionally to cause harm, they need to investigate and prosecute fully. No investigation sends the message that there are no consequences to your actions and could lead them to do it again or encourage copy cats.