Paddock killed 58 people in an attack on a music festival.
The documents also identified a second person of interest in the case.
Some attorneys say MGM's paid room for its security guard could result in him providing a version of the shooting timeline that is favorable to the company.
Stephen Paddock's massive arsenal raises questions about gun regulation and hotel security.
The gunman, Stephen Paddock, had at least 19 rifles and handguns and fired hundreds of rounds of ammunition from his hotel room at the Mandalay Bay hotel.