Washington County sheriff's officers Monday located the wreckage of a single-engine plane with the bodies of three people inside on a mountainside 20 miles north of St. George.

Pilot John Sprag, age unavailable, and passengers Melvin Bondsteel, age unavailable, and his wife, Donna, 55, all of Sundance, Wyo., were killed in the crash, a Washington County Sheriff's Office spokeswoman said.The Piper PA-28 en route from Overton, Nev. to Sundance, crashed sometime Sunday in cloudy, rainy conditions, Lt. Robert Smith of the Utah Civil Air Patrol said.

Relatives reported the plane was missing early Monday morning, but aircraft flying over the Utah-Arizona border not far from the crash site Sunday received an electronic emergency signal from a downed craft, Smith said.

Civil Air Patrol ground searchers from Utah and Arizona combed the border area in southwestern Utah Sunday and continued the search by air at dawn Monday. Despite low clouds and poor visibility, air searchers spotted the craft 1,500 feet from 1-15 about 9 a.m., Smith said.

Additionally, Washington County Sheriff Glenwood Humphries received a report from an eyewitness who saw a plane disappear into the clouds near the crash site.

Humphries and deputies hiked for more than an hour to reach the plane.

"It took the mountain head-on," Humphries said.

A state Medical examiner determined all three died on impact, Humphries said.

The crash occurred in rugged terrain, making access difficult, Humphries said. Officials on horseback were still working to remove the bodies Monday evening.

Federal Aviation Administration officials and National Transportation Safety Board investigators were to arrive at the crash site Tuesday to study the accident, FAA Regional Duty Officer Michael O'Conner said from Seattle.

Relatives said the craft left Overton at 1:30 p.m., and the pilot had planned to stop in Provo before continuing to Sundance, Smith said. No flight plan was filed, he said.