THE PLT & PASSENGERS WERE SEEN DRINKING BEER IN A BAR PRIOR TO THE FLT. AFTER THE ACFT TOOK OFF, WITNESSES OBSERVED IT FLYING VERY LOW NEAR A SHORELINE; ONE OF THEM WAS A POLICE OFFICER THAT IDENTIFIED THE ACFT BY ITS REGISTRATION NUMBER. AT APRX 1930, THE PLT MADE A VERY LOW PASS OVER AN ARPT AT HIGH SPEED & AGAINST THE PREVAILING FLOW OF TRAFFIC. NO KNOWN WITNESSES OBSERVED THE ACDNT. THE WRECKAGE WAS FOUND 3 DAYS LATER WHERE IT HAD CRASHED ON A FEDERAL WILDLIFE PRESERVE & CAME TO REST PARTIALLY SUBMERGED AGAINST THE BANK OF A CANAL. AN EXAM OF THE CRASH SITE REVEALED THE ACFT HAD COLLIDED WITH A HIGH TENSION ELECTRICAL TRANSMISSION LINE AT ABOUT 40 FT AGL, THEN IMPACTED THE GROUND. TOXICOLOGY STUDIES BY THE MEDICAL EXAMINER SHOWED THE PLT'S BLOOD/CHEST FLUIDS HAD AN ALCOHOL LEVEL OF 0.09%. TESTS OF THE OCCUPANTS CHEST FLUIDS AT THE FAA AEROMEDICAL CENTER SHOWED ALCOHOL LEVELS OF 0.115% FOR THE PLT, 0.151% FOR THE FEMALE PASSENGER, & 0.085% FOR THE MALE PASSENGER. THE EXTENT OF POSSIBLE PUTREFACTION WAS NO VERIFIED.