Could he have lured her with the prospect of an apartment? He would be moving out I presume so it may have been true and then turned sinister. He communicated about the apartment, then looked her up online and thought she would be a good victim. He then followed her and that day, he said, "You are looking for an apartment? wow, such a coincidence but we talked online about MY apartment. Why don't you come see it now??"
That scenario would actually answer alot of questions for me as it would explain why she got in the car. Why she got in the car is what most puzzles me. If he had communicated with her before or if she communicated with him and he had mentioned a wife or girlfriend, she maybe would have gotten in the car.
That actually is a scenario that makes a ton of sense. She gets in to get to the apartment meeting. He mentions that he's leasing his apartment and has moved out and offers to show it to her for her to stay there. She walks right in.