missing, as with her new bmw, an engagement gift from john. there was noge sign of the murd weapon t but detectives did recover two 38 caliber slugs and something else that caught the detective's tension. >> on the inside of sherri err left arm then found a bite mark and she swabbed that for a is a line va that could obtain to the killer. >> reporter: saliva that contained dna for anyone who bit sherri. remember, this was 1986, years before dna technology testing could arrive which could link a suspect to a w sample like this one so back then the dna wasn't much nahelp. but the swab was carefully packaged c and bundled with allf the other evidence. for now, detectives didn't have much elseec to work with. no eyewitnesses. no usable fingerprints. no cleare motive, except for