It is really odd that his dad was diagnosed as psychopath with a violent criminal history.  Can genetics be that precisely transmitted, scary if there is an element here?  But, it is probably more likely that as the story unfolds, they will piece together a plausible explanation.  I would not want to be in the Mandalay Bay's shoes, as their liability insurance will be swamped by claims and far exceed the coverage, perhaps hundreds of millions of dollars in claims if they can be proved negligent in allowing the gunman to carry in all those weapons, may have had crushing gambling debts, was seen on video doing suspicious things, etc.  They may have to declare bankruptcy.  No to mention, the liability insurance for other hotels will skyrocket.  Hope HPD learns something from the scale on this, as we are likely on the target list by terrorists, due to our tourism boom.  I think LV will have to create a visible and roving 24/7 super swat team out of this for deterrence and quicker response.