we have his sperm in bonnie craig.spute about this. >> reporter: this was no accident, said the prosecution. it was rape and murder. this man was about to suggest, maybe bonnie craig had a few secrets of her own. >> it was consensual sex. how many people had a different side to them that was different than what family and friends knew? >>> coming up -- the case for the defense. >> you're saying this young woman -- >> i'm saying that's a definite possibility. >> would the jury buy it? happiness is powerful flea and tick protection from nexgard. nexgard kills fleas and ticks all month long. and it comes in an easy-to-give tasty chew. and that makes dogs and owners happy. no wonder vets love it too. reported side effects include vomiting, itching, diarrhea, lethargy and lack of appetite. see your vet for more information on flea and tick protection you and your dog will love. nexgard. the vet's #1 choice. i just want to find a used car start at the new carfax.com show me used trucks with one owner. pretty cool. [laughs] a

craig melvin. >> and this is "dateline." >> i can't believe that your baby is lying there lifeless. >> she was everything to me. she was so sweet to everybody. >> state troopers said bonnied in a hiking accident. >> they said she fell off a cliff. her mother said they were wrong. >> i'm screaming to them, these are defensive wounds. >> no witnesses, no weapon, nothing left behind but a stranger's dna. >> we no longe