THE SURVIVING PAX RPRTD THAT DRG INITIAL CLIMB AFTER TAKEOFF, THE ENG SUDDENLY STOPPED & DID NOT RESPOND TO ATMTS OF A RESTART. THE PLT TURNED BACK TOWARD THE ARPT, BUT WAS UNABLE TO REACH THE RWY. THE ACFT IMPACTED LARGE TREES IN A WOODED AREA, THEN CRASHED TO THE GND & BURNED APRX 1/2 MI FM THE ARPT. AN ENG TEARDOWN REVEALED THE CENTER CRANKSHAFT BEARING HAD SEIZED. THERE WAS A CRACK IN THE ENG CASE IN THE VCNTY OF THE BEARING'S OIL ACCESS PORT. ALSO, THERE WAS EVIDENCE THAT OIL HAD PARTIALLY BYPASSED THE BEARING & FLOWED INTO THE CASE. AN ACQUAINTANCE STATED THAT ON A PREVIOUS OCCASION, THE ENG SEIZED WHILE THE ACFT WAS BEING TAXIED. HE FURTHER STATED THAT THE PLT ADDED OIL TO THE ENG, ROTATED THE PROP, RESTARTED THE ENG, THEN FLEW THE ACFT FREQUENTLY, THEREAFTER. ACQUAINTANCES ALSO SAID THE PLT HAD OVERHAULED THE ENG IN MID 1986, ALTHOUGH HE WAS NOT CERTIFIED AS A MECHANIC. ALSO, THE ACFT HAD BEEN MODIFIED IAW STC SA45RM; HOWEVER, NO RECORD WAS FND CONCERNING THE OVERHAUL OR MOD. A CHECK OF THE PLT'S BLOOD SHOWED AN ALCOHOL LVL OF 0.07%.