Hey y'all, longtime lurker who lost/forgot my old account!
Going off just what we know, I think this does appear to be someone they know. Reason being there was no forced entry AND they appear to have had a very large social circle.
Also, the fact that three men managed to get inside for a welfare check before police would indicate that there were decent # of people who had their key access code or perhaps knew where they stashed a spare key.
The man in the video seems to be walking with intent. He doesn't seem interested in anything but getting to where he is going, and yes, hiding his face. Definitely a strong POI from my POV. Also, he has a bubble butt lol. Someone's gotta recognize that ass.
I don't think this is burglary gone wrong. Yes, that can happen, but generally you don't burglar a place at 2am and not expect people to be home. If the suspect were planning to rob the place, they would have accounted for that, and perhaps, not tried to do this alone or gone back at a time when the house was empty (when most home robberies occur).
The fact they are operating alone, at 2AM-5AM, and able to get into the home without forcing entry, makes me think it is someone who was targeting them specifically. And without knowing more about them, including former relationships, crypto accounts, etc, then impossible to guess why.
Oh and yes my work would call 911 on me after an hour of no-showing. And I am not a doctor. As another person here said, most professionals get to work on time religiously.