On December 20, 1980, teenage sweethearts Sabrina Gonsalves and John Riggins were supposed to attend a birthday party but never arrived. 36 hours later their bodies were found by police in a California ravine. The case went unsolved. Then in 2002, using advanced DNA technology, police were able to match samples stored in a FBI database to a convicted rapist. “48 Hours" correspondent Troy Roberts reports. This classic "48 Hours" episode last aired on 5/17/2014. Watch all-new episodes of “48 Hours” on Saturdays, and stream on demand on Paramount+. Learn more about your ad choices. Visit megaphone.fm/adchoices