(CNN) -- Four Americans were killed in a small plane crash in northwestern Mexico, the president of the volunteer organization Flying Samaritans said Saturday.
The plane had been headed on a medical mission in the Mexican state of Baja California and lost radio contact with the ground on Friday afternoon, said Flying Samaritans President Victor Jones.
The wreckage of a Beechcraft A36 plane and the bodies of the four volunteers were discovered Saturday "after an extensive ground, air and water search," Jones said in a statement Saturday.
The wreckage was located in rough terrain about 30 miles south of Ensenada, Mexico -- a city on the Pacific coast -- where the plane had departed Friday afternoon en route to San Quintin, Mexico.
Jones said that Mexican authorities found four bodies in the wreckage.
Radio contact with the plane was lost shortly after the pilot reported to the Ensenada airport on Friday when it was about 10 miles south of the airport, Jones said.
He identified the victims as: James Thornton, a plastic surgeon; Graciela Sarmiento, a doctor; Andrew Theil, a non-medical support staffer; and Roger Lyon, the pilot.
Flying Samaritans transports medical and support personnel to clinics in Baja California -- which is just south of California, the American state -- where they provide free medical services and supplies to those who lack medical care.
CNN's Chuck Johnston contributed to this report.