ACFT WAS SEEN DESCENDING IN A NEAR VERTICAL DIVE AT A HIGH RATE OF SPEED WITH NO ROTATION ALONG THE ROLL AXIS. THE ACFT CRASHED NOSE FIRST INTO A NEWLY PLANTED CORN FIELD. POST CRASH EXAMINATION OF THE ACFT STRUCTURE, FLIGHT CONTROLS, AND ENGINE REVEALED NO EVIDENCE OF PRECRASH MECHANICAL FAILURE OR MALFUNCTION. THE INVESTIGATION REVEALED THAT THE PILOT HAD EXPERIENCED MEDICAL PROBLEMS WITH CANCER; HIS BROTHER HAD DIED FROM CANCER; HIS FATHER HAD DIED THREE MONTHS BEFORE; AND HIS MOTHER-IN-LAW, WHOM HE WAS CLOSE TO, RECENTLY HAD A STROKE. THE PILOT'S WIFE INITIALLY STATED THAT SHE BELIEVED THE PILOT HAD INTENTIONALLY KILLED HIMSELF. THE PILOT WAS ON AN UNSUPERVISED SOLO BUT HAD NOT BEEN CLEARED OUT OF THE TRAFFIC PATTERN. THE ACCIDENT SITE WAS 11 MILES FROM THE AIRPORT. THE MEDICAL EXAMINER RULED THE MANNER OF DEATH AS SUICIDE.