In my theory, I suggested that he offered her a ride as a ruse but quickly made an excuse that he forgot something, and it would be just a minute to get it. If she knew him, even for a short period of time, she may have thought it was okay to just go for the ride. The only thing about this is, her sister was locked out of the house, because she had to go to gradma's to let her in. Jennifer had the key. So what did he say to keep her in that truck? Threats of a knife or gun would make her stay put.
I have so many questions about the boldness of his approach in this case.
Why wasn't he concerned that people would see the truck at 3pm and ID it? Or even get a plate number, coming or going? Maybe the tags were not to this truck and it wasn't registered.
No signs of a struggle, could be that he knew her well enough to get her into the truck or again, a gun. But he didn't shoot her or stab her. So that is why I think she knew him. Just met him, probably a good looking, older guy, like early 20's or mid 20's. There is always the possibility there were two also. It would be hard to drive a truck, come on a person and get them into the truck without screams or a fight. All of her stuff was taken with her, she didn't drop anything, or leave it behind. I picture her, getting in, tossing the bookbag, clarinet case in the back seat.
Also the truck was open in the back, so there had to be a back seat, to transport the body. It didn't have tinted windows, so people could see what was in the truck if they were in a two lane at a stop light. So he had to have covered her up, and taken back roads, remember it is FL and daylight for longer here, even in February. If he was married he had to get back home, if he was single, he could have taken her back to his place or anywhere really and no one was waiting on him to be home at any given time. Or his wife was out-of-town. These are things I think about in this case. How brazen he was.