MISSOULA, Mont. (AP) — The CEO of an Arizona-based welding company and one of his employees were killed in a plane crash in northwestern Montana.

Lincoln County Sheriff Roby Bowe says Stinger Welding Inc. CEO Carl Douglas of Coolidge, Ariz., and John Smith, also of Coolidge, died in the crash late Tuesday or early Wednesday near Libby. Douglas was piloting the twin-engine Beechcraft. Bowe says the men left Coolidge, Ariz., at about 8:30 p.m. on Tuesday and were to arrive in Libby just after midnight.

Colleagues reported the men missing Wednesday morning. A Montana Aeronautics airplane was able to locate the plane's emergency locator transmitter signal. Bowe says search and rescue crews reached the site at about 8 p.m. Wednesday.

The National Transportation Safety Board is investigating.