The pilot and passenger crashed while taking off from a private airstrip near Freeport Saturday afternoon.
Family members of the two men watched in horror as the aircraft went down.
Members of an NTSB investigation team spent most of Monday morning inspecting the wreckage of the two-seat aircraft, looking for clues as to what caused Saturday's deadly crash.
They're checking the engine, the fuel tanks, anything that could have led to the tragedy.
The crash was especially horrible for the families of Fred Bogle of Seagrove Beach, and Ruben Rios of Tallahassee.
Bogle was taking the single-engine aircraft up to show Rios property he was interested in buying. During takeoff something went wrong. Bogel's wife, a pilot herself, witnessed the accident.
Authorities carried the wreckage to a nearby hangar for further inspection. The entire case could take between six to nine months.
The engine will be sent to the manufacturer for further testing. Investigators are also waiting on autopsy and toxicology reports, which may provide answers to the cause of the crash.