The group also says it was the year's 273rd mass shooting, in which at least four people were wounded or killed.
Authorities are still investigating why 64-year-old Stephen Paddock carried out the murders.
"Mr. Paddock was a customer and purchased firearms from our store; however, all necessary background checks and procedures were followed, as required by local, state and federal law", Chris Sullivan said. He lived in a retirement community in the area, Metro said.
The shooting broke out on the final night of the three-day Route 91 Harvest festival, a sold-out event attended by thousands and featuring top acts such as Eric Church, Sam Hunt and Jason Aldean. All four of the 2015 mass public shooting in France involved machine guns, including the 130 people killed in November of that year in multiple attacks including one at a concert venue. The concertgoers ducked for cover, ran, or screamed out of fear. "It would sound like it was reloading and then it would go again", Smith said. "And they'd start again and the girl standing right behind me, about two feet, she got shot in the stomach".
The SWAT team used the alarm triggered by the smoke to zero in on Paddock's position in about 20 minutes - not almost enough time for a floor-by-floor search of the hotel, which has 3309 rooms and a 12,000-square-metre casino.
The firearms found in the hotel had calibers ranging from.308 to.223, and a handgun was also among the weapons.
Video and pictures from the scene show confusion and terror at the indiscriminate attack, and the tense hours of emergency organizing and rescue that followed.
Fennewald said some signs people should pay attention to are behavioral changes in a person, even if they are small.Some behavior changes may not lead to law enforcement getting involved.
Authorities have said that the suspect checked into his hotel room on Thursday. Police said early Monday that she has since been located. Besides the Puerto Rico trip, Trump will travel to Las Vegas Wednesday to meet with families of the dead.