DESERT CENTER, Calif. -

An investigation was underway today into the crash of a small plane that killed both the pilot and his passenger in Desert Center.

The plane crashed around 1:30 p.m. Monday in the desert area east of Kaiser Road between Lake Tamarisk and a First Solar energy site, said Sgt. Thomas Velarde of the Riverside County Sheriff's Department.

The victims, identified as Mike Cyr and Jeff Randall, were both civil supervisors at the Desert Sunlight Solar Project, according to First Solar CEO Jim Hughes.

"We extend our deepest condolences to Mike and Jeff's families and loved ones. We are in contact with the families, and are providing our support in this difficult time," Hughes said.

A deputy from the sheriff's Colorado River Station and a federal Bureau of Land Management ranger were patrolling the area when they saw the plane flying out of control and crash, Velarde said. The plane was a single-engine 1971 Grumman American model AA-1A, he said.

The crash was being investigated by the National Transportation Safety Board and the Federal Aviation Administration, Velarde said.