BFR DEPG ON A HUNTING TRIP, THE PLT & PSGR LOADED THE ACFT WITH BAGGAGE, WHICH INCLUDED 4 DOGS & THEIR CAGES. BFR TKOF, THE PSGR STRAPPED HIMSELF IN THE RGT FNT SEAT. THE PLT TOOK OFF WITH AN IFR FLT PLN IN IMC CONDS. SHORTLY AFTER TKOF, THE ACFT CRASHED ABT 1-1/2 MI SOUTH OF THE ARPT. A WITNESS SAID THE ACFT SOUNDED LWR THAN NML WITH THE ENGS AT HIGHER THAN CRUISE PWR SETTING. HE INDCD THE ACFT CIRCLED HIS HOUSE, THEN THE SPD INCREASED. HE SAW THE ACFT COME OUT OF CLD BASES IN A NOSE DWN, RGT BANK ATTITUDE. THE ACFT CRASHED ON WOODED TRRN, HIT A HOUSE & BURNED. IT WAS DESTROYED BY IMPACT & GND FIRE; THE OCCUPANTS WERE FATALLY INJURED. NO PREIMPACT PART FAILURE/MALFUNCTION WAS FND. THE CTL YOKE WAS FND PSND TO THE LEFT (PLT'S SIDE). THE PLT'S BLOOD TESTED NEGATIVE FOR DRUGS. ALTHO HIS BLOOD TESTED POSITIVE FOR ETHANOL, THERE WAS AN INDCN OF POST-MORTEM PRODUCTION OF ETHANOL (PUTREFACTION). MED RECORDS SHOWED THE PLT HAD BEEN TREATED FOR HYPERTENSION WITH THE DRUG ATENOLOL; TOX TESTS SHOWED THE PRESENCE OF ATENOLOL IN URINE, BUT NOT IN BLOOD.