It was a Smith & Wesson 342 AirLite Ti .38 caliber revolver, according to the report. The responding officers could see that it appeared to be a self-inflicted gunshot wound to the head and the autopsy revealed that there was "a gunshot wound to the upper palette inside the decedent’s mouth with obvious damage to the upper teeth," so the cause of death was "an interoral gunshot wound and the manner of death was ruled a suicide."
An interesting tidbit from the report about the revolver is that it was the only gun at the hotel that was purchased before his buying spree that began in October 2016.