This photo released on April 23, 2012 by the Utah County Sheriff's Department shows one of the booby traps taken from a crude shelter made of dead tree limbs found in a Provo Canyon. Two men have been arrested on suspicion of setting the traps and were booked Saturday into the county jail for investigation of misdemeanor reckless endangerment. - AP Photo

 SALT LAKE CITY: A deadly booby trap rigged along a popular Utah trail could have killed someone if they had tripped a ground wire set up to send a 20-pound (9-kilogram), spiked boulder swinging into an unsuspecting hiker, authorities said Monday.     

Another trap was designed to trip a passer-by into a bed of sharpened wooden stakes, authorities said.   Two men arrested over the weekend on suspicion of misdemeanor reckless endangerment told authorities the traps were intended for wildlife, but investigators didn't believe the story.

''This is a shelter put together by people, visited by people  anything that would be impacted by their device would have to be humans,'' Utah County sheriff's Sgt. Spencer Cannon said. ''It took some time to build these traps.

They took rope, heavy-duty fishing line, and they intended what the traps were going to do.''   The booby traps were set at entrances to an elaborate dead-wood shelter built by the suspects that could have caught the attention of children, Cannon said.

The structure was easy to see, Cannon said, but the booby traps could have been overlooked by everyone except a military-trained officer like James Schoeffler of the US Forest Service, who was on a routine patrol along Big Springs Trail last week when he noticed the trip wires.

Schoeffler was trained in hazardous device detection.

This photo released on Monday, April 23, 2012 by the Utah County Sheriff's Department shows part of a booby traps found along a hiking trail as part of a crude shelter made of dead tree limbs found in a Provo Canyon, Utah. Two men have been arrested on suspicion of setting the traps and were booked Saturday into the county jail for investigation of misdemeanor reckless endangerment. - AP Photo

''A lot of people go up there after dark, as well,'' Cannon said. ''We're very, very fortunate that it was Officer Schoeffler who found it.''

The US Forest Service has not made Schoeffler available for an interview. Authorities said he disabled the traps after taking photos and video of the site.    The area is located in Provo Canyon, a popular hiking spot a few miles (kilometers) from downtown Provo. Cannon said the traps were just a half-mile (800 meters) from a busy trailhead.

''Who goes up this trail thinking, I'm going to have to look out for booby traps?'' Cannon said. ''A kid could say, 'Oh cool, a shelter,' and run right across the trip line.'' Authorities said a tipster alerted them about comments on Facebook that mentioned the traps and the shelter. Detectives then tracked down the suspects, Cannon said.

Benjamin Steven Rutkowski, 19, of Orem, and Kai Matthew Christensen, 21, of Provo, were booked in the Utah County Jail on Saturday and released on bail.    Prosecutors believed the misdemeanor reckless endangerment allegations were the strongest claims they could pursue without anyone being injured. Charges have not yet been filed.

Rutkowski's father, Steven, declined comment. No phone number was listed for Christensen, and it wasn't immediately clear if either suspect had an attorney.