The man suspected of opening fire on thousands of concertgoers in Las Vegas, killing more than 58 and injuring hundreds, had roughly 19 guns in the hotel room from which he carried out the shooting, sources familiar with the investigation said.
Investigators are working to determine what type of weapons were used by the suspect, Stephen Paddock, 64, of Mesquite, Nevada, who police say killed himself by the time officers arrived at his room.
The probe will also look at where the suspect got the weapons and whether they legally obtained and licensed.
In Nevada, it is legal for people 18 and over to carry a firearm openly without a permit, according to the website of the gun-rights organization, NevadaCarry.org.
Steve Gomez, an ABC News consultant who is a former Los Angeles police officer and FBI special agent, said the open-carry law in the Silver State means that virtually anybody can carry a gun in most places.
"It's like the wild, wild West," Gomez said.
Gomez also said if the weapons the suspect had are found to be fully automatic, as opposed to semi-automatic, those "would have been illegal in Nevada and under federal law unless he had a federal license or tax stamp... just like in most states."
Nevada does allow, however, rifles considered to be assault weapons and has no limit on the magazine-capacity for firearms, according to NevadaCarry.org.
"There are no purchase permits, gun registration, or gun-owner licensing," the gun-rights website says. "There is no waiting period mandated for firearm purchases."
It is also legal in Nevada to purchase or sell a machine gun or silencer so long as the item is registered and meets federal regulations, the National Rifle Association says on its website.
Nevada law allows rifles and shotguns to be carried in cars.
But it prohibits having a round in the chamber of a gun that is in a car, according to state statutes.
It is also illegal in Nevada to carry a gun in a concealed manner without a permit or to carry a loaded or unloaded firearm in a bag without a permit, according to NevadaCarry.org.