Just a few thoughts:
There appears to be an approximate window of just over five hours from when Jennifer was abducted until her vehicle was dropped off by the unknown person. According to reports, she would have left her condo between 7:30 A.M. to 7:45 A.M. to go to work. Per the time on the security camera at the location where the car was left, the time is 1:00 P.M. As it is just over one mile from her condo to where the car wound up, you wonder where the vehicle was during that time frame. Was it in that immediate area or driven to another location? If it was a considerable distance, it would have had to have been somewhere with-in a 2 1/2 hour drive. However, since it was parked so close to where she lived, you wonder if the person who left it did that so he/she would have only a short walk to where they might have been living or working. One theory I heard was the person probably did not have the use of a vehicle of their own and that's why Jennifer's was taken.
It was reported that investigation of Jennifer's car after it was impounded resulted in one fingerprint being lifted that did not match anyone who normally would have used that vehilce. Attempts to match that print with those on file in the related computer system was negative. Maybe the person with that print had no previous contact(s) with law enforcement or, if so, that agency had not entered it in the system perhaps because the arrest was for a less-serious matter. In looking at photos of the car after authorities impounded it, there seems to be quite a bit of white material on the inside door area. Could that be an indication of the unknown person's profession such as painter, plaster? or the like?
It was reported that Jennifer's purse and brief case were never found. Could these have been left wherever she wound up or discarded elsewhere? It should be noted that the individual shown in the security video is not carrying any such articles.