GUTHRIE CENTER, Iowa - Authorities believe the pilot of a small plane that crashed in central Iowa, killing all four people on board, may have suffered a heart attack.

The Guthrie County Sheriff’s Office says in a news release that a student pilot was going to attempt an emergency landing Friday night because the pilot apparently had a heart attack, but the plane dropped off radar southwest of Guthrie Center airport.

The wreckage was found Saturday morning in a cattle pasture southwest of Guthrie Center, about 115 miles (185 kilometers) southwest of Le Mars, where the plane had taken off.

The sheriff’s office identified those killed as the pilot, 49-year-old Edward Ralph Anderson, of Le Mars; 28-year-old Tyler Douvia, of Merrill; and 36-year-old Patrick Kellen and 15-year-old Samantha Clark, both of Le Mars.