I don’t know that he killed or shot any.
In order to establish that, you have to know that no one else was in the room with him.
As of right now, that has not been adequately demonstrated.
I have made multiple posts on this subject already.
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.
If none were killed in the perfect kill zone it does not matter whether or not he was alone.