I have held the theory that Steven was looking for work when he disappeared. But,try as I might, I cannot visualize any scenario that has a potential employer murdering him, either in a home in Anthem, or out on the links. The stats of people murdered while interviewing for a job must be tiny ; in fact I have never heard of it happening.
The family at one time thought Steven might have gone to Brazil, where he had done a mission at one time. He speaks Portrugese, and has his passport with him ; I thought that might have somehow happened. But, then I found out from the Brazilian Consulate that any American entering Brazil MUST have an entry visa. It would have left a very easy paper trail. I wonder if LE or the family have pursued that ?
I also wondered if that actually is Steven on that brief,grainy video. Yes, I know the family thinks it is ... But, the scenthounds never picked up any trace of him at all. Odd.
So, all that's really left is that Steven (if it is him) , was meeting someone,going someplace with someone, in a vehicle. I'm guessing that he walked to a home, and the person(s) was/were waiting for him in the vehicle.