according to colleen barnett, from the district attorney's office, that was because they made some earlyt the crime scene. >> officers had investigated burglaries and robberies for many years before they get into homicide. -- they were open a little bit but nothing was tossed. >> but what about those items that were lost detectives took careful notes of those notes. >> cameras, the bicycle, there was some painting equipment that were easy to take that were not taken. and the stuff that was taken and put in a backpack was left in the garage. did make sense. >> the home, to investigators, should no sign of forced entry. the garage door was the only way in for the intruder. but it looked as though it could've been staged. now to investigators, this didn't look like a burglary gone bad, but more like a targeted killing. and they theorize their suspect. it was somebody who is already inside the house. >> coming up. >> my memory is so bad. >> how murky was her memory, really? investigators are about to listen very carefully to sandra's story. when dateline continues. the lungs and lower airway