Federal investigators were working Monday to determine what caused a small plane to crash in east Alabama Sunday night killing the pilot.

Calhoun County Coroner Pat Brown told local media the pilot was identified as Harvell Walker Jr., 70, of Fayetteville, Georgia.

Walker was reportedly the only person on board the small, single-engine RV-8 airplane when it crashed into woods near Weaver.

U.S. Air Force radar operators apparently tipped off local first responders that the small plane appeared to have disappeared on radar. That led to a search that ultimately found the crash site.