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, 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 U.S. 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.

“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 area is in Provo Canyon, a popular hiking spot. Cannon said the traps were just a half-mile from a busy trailhead.

“Who goes up this trail thinking, ‘I’m going to have to look out for booby traps’?” Cannon said.

Authorities said a tipster alerted them about comments on Facebook. Detectives then tracked down the suspects.

Benjamin Steven Rutkowski, 19, of Orem and Kai Matthew Christensen, 21, of Provo were booked in the Utah County Jail on Saturday and freed on bail.