Elias Johnson of the Pinal County Sheriff's Office said three men and three children were killed in the Wednesday crash, the Los Angeles Times reported. He said he visited the mother, a Pinal County resident, Wednesday night.
"The mother is a pilot herself," Johnson said, adding she understood there was little hope for her children given that the plane, going 230 mph, had flown "directly into the face of the mountain."
The body of one child was recovered by Thursday morning, KPHO-TV reported.
Pinal County Sheriff Paul Babeu said the plane crashed Wednesday in the Superstition Mountains when returning to Safford from Mesa after picking up three children. Besides the pilot, a mechanic and another adult were on board.
Johnson said rescue personnel were using infrared devices but haven't detected any sign of movement, The (Phoenix) Arizona Republic said.
The Rockwell AC69 twin engine aircraft "crashed under unknown circumstances" in the rugged terrain, Federal Aviation Administration spokesman Allen Kenitzer said in a statement. The plane is registered to Ponderosa Aviation in Safford.
The FAA and National Transportation Safety Board are investigating.