His dead body was obviously tested for powder residue to confirm he was the shooter. Vegas hotels have cameras everywhere, you can bet they have combed through the footage to identify every single person that was in the hotel that night.
For the nth time, there were no security cameras in the guest areas of the 32nd floor. In fact, I think it is standard practice In Vegas NOT to have security cameras in the guest room areas.
It isn’t very hard to figure out why that may be the case.
And there may have been a possibility that another person escaped via stairwell UP to the Four Seasons, which starts on the 35th floor of the same building.