a georgia cop on blood mountain had found the bayonet wrestled away from gary hilton. nteresting about that knife is, before we knew of mr. hilton, before he had killed ms. emerson and been caught, our analyst in our lab showed us, this is the style -- this is what the knife's going to look like. >> cameras and memory cards were found inside the van. the techie detectives in the fdle computer lab were working overtime trying to unscramble deleted material from the evidence. and deep in their dna lab more than 700 samples were being analyzed in an attempt to find some link between gary hilton and the late sheryl dunlap. had gary hilton managed to outsmart them all? would florida be able to make the case against him? four years after sheryl dunlap's death, it was finally going to trial. coming up -- >> your palms are sweat wri and your heart is beating. >> the dramatic case begins. how would it end? >> you could just see the jurors, i saw it in theirize, they knew. >> when with "dateline" continues. i'm so frustrated. i just want to find a used car without getting ripped