Federal agencies have started preliminary investigations of debris left from a medical plane crash in Lake Michigan that killed four of the five people aboard.

National Transportation Safety Board and Federal Aviation Administration personnel are examining plane wreckage lifted from Lake Michigan on Sunday evening.

READ MORE: Detroit Institute Of Arts' "Inside Out" Program Expands To 4 Oakland County Parks

NTSB spokesman Keith Holloway said Monday that they’ll spend at least a day in Ludington before moving the investigation to Detroit.

Earlier Sunday, the body of the fourth and final victim crash victim, co-pilot Earl Davidson, was recovered.

READ MORE: Multiple Beaches, Including In Oakland County, Closed Due To Bacteria Levels

The plane was en route to the Mayo Clinic in Rochester, Minn., with a cancer patient and four others on board when mechanical problems caused it to crash July 23. The 66-year-old pilot, Jerry Freed, was the only survivor. He was rescued that day.

The bodies of Alma school superintendent and cancer patient Don Pavlik and his wife, Irene, were found Friday and a third body identified as Dr. James Hall was recovered Saturday.

MORE NEWS: Detroit Police Officer, Suspect Killed In Shooting On City's West Side

© MMX WWJ Radio, All Rights Reserved. The Associated Press contributed to his report.