I had heard the sexual harassment claims elsewhere but couldn't bring them here at that time. I am curious if the person was fired or continued working at Panasonic. Of course, with something like that in her past, LE would likely hone in on the harasser immediately as a suspect, but some people just don't care and are going to do what they want to do regardless of the potential to be caught. However, I don't know that I think it's this person. LE would have been able to get his name from their work. If they could not locate this man (or were able to locate him and he had this kind of truck or did not have an alibi for that morning, etc), I feel he would have already been named a suspect. However, it is possible he borrowed/stole/somehow accessed the truck another way, had someone give him an alibi for that morning, etc., so I won't rule him out completely.
As far as her date the day before, it sounds like her brother doesn't feel it is that person. I am also leaning away from that person, but again, IMO I am not completely ruling him out. It's possible that during their time chatting on whatever app this was and during their time on their date, she may have told him about her morning routine, including sitting in her car for 15 min talking on social media. If he had nefarious intentions from the get go, this would have been the perfect opportunity for him. Still risky, as he has no idea who she told his name to, but some people don't care.
As of right now, I think my #1 theory is someone who knew her/knew of her but she either didn't know them at all or it was someone kind of on the periphery of her life - like maybe a coworker or former coworker she didn't interact with much but who got infatuated with her. A Walmart employee who would see her pull in every day. Maybe even someone who had run into her at that gas station in the past and followed her. MOO