I'm thinking that rather than someone not liking him, the opposite was true. I'm wondering about the possibility of a stalker of sorts. It would be some acquaintance, probably not that close friend-wise who perhaps became obsessed with him. They chose late evening so that with the cold there wouldn't be many outside to witness his leaving whether voluntary or forced. They could have had some story to get him to leave with them. Since it's the holiday time there are ample stories that would sound plausible. It would seem their desire was to leave no evidence. If they entered his residence they probably touched nothing and waited for him to come along and close and lock his door. If he suggested taking his cell phone the person probably told him that they had one so he didn't need his. (I'm not sure from the stories if he had one and if he did if it was still at his residence.) Since his job was at the University and based on his friendliness (which is consistently mentioned in news stories) he most likely knows many people through his work. Initially, at least, their motive would not to be to harm him. Since there's been no ATM activity or calls it seems like whoever is trying to avoid any detection or trails. To go to these extremes would seem to mean that he knew them well enough to identify them and they are, perhaps, not in a position to simply disappear themselves after committing such a crime. One of the bad things about this scenario is the huge amounts of potential suspects it would involve. There's always the possibility of a random stranger being involved, but I don't think they would have been as careful as far as eliminating leads.
