Mountain bikers and runners, beware: Fishing line “traps” wrapped around trees on the Captain Jack’s and Sesame Trails at North Cheyenne Canon Park could seriously injure trail users.

The “who” and “why” remain unknown, but some bikers on the Colorado Mountain Biking Facebook group have pointed the finger at local hikers who they believe do not wish to share the trail with riders. A Gofundme campaign is currently seeking to raise $6,000 to install trail cameras in the area.

This isn’t the first time in recent years that trail users have had to contend with dangerous traps. Last February, a North Carolina park closed its trails after one of 60 hidden nails impaled a runner’s foot. In 2012, two Utah men were arrested for planting traps, including a swinging, face-level rock covered in sharpened stakes, on a trail in Provo Canyon.

In July 2017, a mountain biker in Calgary raised some $8,000 on a crowdfunding site, claiming that he suffered injuries to his neck after riding into a length of barbed wire strung across a trail. He was later charged with fraud after authorities determined that he had injured himself riding an ATV on private property.