I haven't followed this case for a long time, but I thought the general consensus was that their disappearance was due to a love triangle, a jealousy thing involving her ex. Was the pizza delivery time frame ever explained?
Earlier on this case it said Jon and Audrey were not dating exclusively and that she was dating someone else who suspiciously reported his car stolen and torched the car. No other information was given but the other boyfriend was never named as a suspect or person of interest