Two teenagers found dead of apparent carbon monoxide poisoning in their pickup truck in Scottsdale, Ariz., had just participated in a Professional Rodeo Cowboys Association competition.

Mike Hillman and Jesse Andrus, both 18-year-old high school seniors from Roswell, N.M., had traveled to Arizona last weekend to compete in the Fiesta Days Rodeo in Cave Creek, Ariz. Hillman won the saddle bronc riding competition, his first win ever in a PRCA rodeo. It was the first PRCA rodeo that Andrus competed in.

Hillman and Andrus had been scheduled to return home to New Mexico on Monday. When they didn’t show up, their parents reported them missing.

Scottsdale police found both young men dead in the camper shell of their truck, which was parked in a Safeway parking lot. Police suspect that the youths had a generator running at night, and that it emitted carbon monoxide fumes that killed the pair.

Goddard High School in Roswell, which Hillman and Andrus attended, has brought in a crisis intervention team to help students cope with the deaths.

Two teenagers from Roswell, N.M., died inside the camper shell of a pickup truck in Scottsdale, Ariz., of carbon monoxide poisoning, according to The Arizona Republic.

The two victims, Jesse Andrus and Michael Hillman, both 18, had traveled to Carefree, Ariz., for a rodeo last weekend.

They were both found Monday in their truck. Scottsdale police believe that the youths had been running a generator in the rear of their vehicle to keep warm.

The teens’ parents in Roswell had expected them back home on Sunday, and they apparently contacted Scottsdale police Monday morning when the youths didn’t return.

Using a telephone GPS, police located the teens’ truck, which was parked in a shopping-center lot near Scottsdale Road and Pinnacle Peak Road. Authorities forced their way into the camper shell, and found Andrus and Hillman dead.