Maybe, there is video of BM rolling luggage or something to and from the room. Maybe, that's why he said that he was hauling his tools into the room, when in fact, SM was in a rolling bag. With the coworker stating that there were no tools in the room sure puts BM in a bind to explain. Judge Judy would say, "If it doesn't make sense, it's a lie." I think the entire story is bogus.
I also am totally perplexed that he calls this coworker to come to Denver to complete an urgent job. Yet, BM leaves and never talks to this coworker again, not to explain what happened or instruct him to start work on the emergency job.
The reason that I still lean towards premeditation is that SM's body hasn't been found. That takes some thought and planning.
While I'm at it, why would you go to a hotel room the day before a job that is two hours away unless you are setting up an alibi? If the job runs long, wouldn't you just stay that night after work and finish the next day?
Why would you take personal insurance papers to the hotel room with you? If they were scattered about, I would look at what my boss left in the room. I wouldn't open his mail or read the papers at length; however, I would wonder if they were related to this urgent job over Mother's Day weekend.
BM can still save face and say that SM's death was an accident and he panicked. Unless the COD is apparent, he probably will be able to negotiate a plea deal.