Jen's car is obviously very important to her disappearance but how it fits in is still very much a part of the mystery.
It is not that rare for someone to be abducted in their own vehicle. The abductor generally establishes control with a weapon and has the victim drive. The victim has the option of getting into an accident, attracting attention of a patrolman or just fleeing the car. An older, more savvy victim would be more likely to do this. Why didn't Jennifer (if that is what happened)? An abductee might be expected to take the abductor where he told her if she was satisfied that he would not hurt her if she obeyed. The abductor would probably try to reassure her of that but I would think, for that ploy to work, he would have to either very persuasive or Jen knew him.
The victim could be disabled and or restrained. You wouldn't expect that to occur at a public space where other people might see or hear it. It seems there were not many people around there at 7:30 but a woman's screams can travel quite a distance and there were other workmen around at that time. Whatever happened, whenever it happened, it seems to have been done quickly and quietly.
Two men could have done it. This is less common for a sex related crime and extremely unusual for a personal "relationship" crime but it can't be ruled out. The fact that the DVD was still seat belted in argues against it but doesn't exclude it.
There is the chance that the perpetrator's own car was used and Jen's was moved as some sort of staging but this seems extremely unlikely. There would be some tactical advantage to moving her car. It would be consistent with voluntary absence as opposed to Jen being missing from her apartment with her car still in its assigned space but, if the risk and effort to move the car was taken, it would have been done early, when there was less chance of being seen and no one was aware Jen was missing. One does not have to be a criminal genius to know that you do not want to be anywhere near the crime scene once people might be aware of the crime and paying attention to details. The perpetrator did not go back and move the car around noon.
Most likely, the perpetrator had Jen's car, that was used in her abduction, and as one detail of the process, he had to return to the Mosaic (to fetch his own car perhaps). He left it at HOTG because he didn't want to be seen with it anywhere near the crime scene and perhaps because he saw the advantage of delaying the finding of the car, but the primary reason for his actions was that he need transportation back to Mosaic.
One thing I have considered is that Jen's car was really unsuitable for transporting a dead body; particularly the size of Jennifer. I am not sure she would even fit in the trunk and a body in the back seat with the DVD box would be visible to people in other vehicles, particularly during periods of heavy urban traffic in daylight. In addition, dead bodies usually will discharge some body fluids. There were no indications of this in the car. Assuming she was murdered, she was either taken directly (while still alive) to where her body was disposed or she was later moved in a different vehicle. This would be different from the more typical sexual predator abduction where the victim is abducted from a place of opportunity, transported to a place the predator feels comfortable to do whatever he intends to do, then to the the dump site that serves his purpose.
There is the chance that Jen left in her car not under duress and she met her abductor after she had left the Mosaic (and was either abducted directly or consensually joined with the person who abducted her. For this scenario to work, we would have to explain why this abductor would need to return to the Mosaic at all
Yes, I can certainly see any of this. Again I go back to other crimes such Christina Morris' abduction where the abductor had walked into a parking garage (seen on video) and his car is on video leaving the garage. He and Christina walk in the entrance at 3:55 and his car leaves at 3:58. In 3 minutes they walk to their cars, he abducts her and puts Christina in the trunk of his Camaro (a trunk as small or smaller than Jennifer's), enters his car, starts it and leaves the garage in 3 minutes. A blitz attack doesn't take long for some abduction. An even more relevant case is Kelsey Smith who was abducted in a Target parking lot in Overland KS. The attack, captured on surveillance, was over in a few seconds and the abductor took her to an undeveloped location where he raped and murdered her.
This type of attack could have happened to Jennifer.