Janelle Cruz was killed in Irvine in May 1986. She was eighteen years old. Her death would be the last crime that investigators ultimately attributed to DeAngelo through his guilty plea. After May 1986, the murders stopped.
What was not known, and would not be established until 2001, was that the Northern California rapes and the Southern California murders were the work of the same person. The geographic distance, the apparent change in the nature of the crimes from assault to murder, and the poor communication between agencies investigating crimes in different jurisdictions had kept the cases separate in the investigative records. The connection was made when DNA technology had advanced enough, and when the available evidence from both sets of cases was tested, to show a biological match between the rape kit evidence from Sacramento and the murder-scene evidence from Southern California.
Preserved Evidence and the DNA Link
The 2001 DNA match that connected the Northern and Southern California cases was the result of a decision made years earlier to preserve biological evidence from the crime scenes in conditions that allowed future testing. This was not guaranteed. Evidence preservation across decades of case inactivity requires institutional commitment, adequate storage conditions, chain-of-custody documentation, and the kind of organizational continuity that keeps case files intact through personnel changes, budget constraints, and the ordinary entropy of any large institution.
Several agencies, working independently in their respective jurisdictions, had done this work. The DNA profiles developed from the rape kit evidence and the murder-scene biological material were not always stored in compatible systems; the 2001 connection came when investigators were specifically looking at the possibility of a link and had both sets of samples tested against a common reference.