AT APRX 2330 EST, WITNESSES NEAR THE CRASH SITE HEARD AN ACFT, & SHORTLY THEREAFTER, THEY SAW A FLASH. ONE OF THEM, WHO WAS DRIVING A CAR, WENT BACK TO THE AREA THE NEXT DAY & FOUND THE ACFT WRECKAGE. THE ACFT HAD CRASHED & BURNED ABOUT 1 MI FROM THE APCH END OF RWY 24. WRECKAGE WAS STREWN ALONG AN AREA OF ABOUT 250 FT LONG & WAS ORIENTED ON A HEADING OF 230 DEG. THE ACFT WAS DESCENDING IN AN ESTIMATE 40 DEG DIVE WHEN IT HIT THE GROUND. AN EXAM OF THE WRECKAGE DID NOT DISCLOSE ANY EVIDENCE OF A MALFUNCTION. ABOUT 3500 LBS OF MARIJUANA WAS FOUND IN THE WRECKAGE. THE 2010 WX AT THE ARPT WAS: INDEFINITE 500 FT OBSCURATION, VISIBILITY 1 1/4 MI WITH RAIN & LIGHT FOG, TEMP 33 DEG, WIND FROM 280 DEG AT 5 KTS. ANOTHER PLT HAD LANDED AT 2015. HE SAID HIS ACFT HAD ACCUMULATED A TRACE OF RIME ICE. AT THE TIME OF THE ACCIDENT, WITNESSES SAID THE ROADS WERE LIGHTLY COVERED WITH ICE SNOW.