. >> darla davis was worried. body was barely cold when the prosecutor, davis, jumped on the case and encountered the problem. >> the fact that she lived by herself. >> there was a man wanting to change the single status and there was certainly reason to look at them carefully. but the prosecutor worried too about another possibility. >> we might have a stranger on stranger offense. which is way harder to solve. >> essentially the dead body, not much evidence around and no idea who did it. >> exactly. and i decided we were going to monday morning quarterback the crime scene right away. >> she and the investigators went back to diane's house and took a more in-depth look. >> went over it with the alternate light source. to do it in the dark you would take it and put it on carpeting and any kind of fabric or the wall or anything and certain things will flores. >> the ultimate -- we were looking for semenal fluid. >> it did not look like diane was sexually assaulted, but they had to know for sure. when they tested. >