Las Vegas undersheriff Kevin McMahill told CNN that at least eight guns were found in the hotel room on the 32nd floor of the Mandalay Bay hotel where Stephen Paddock launched his deadly attack, killing more than 50 people and injuring over 400 others.
However, Las Vegas sheriff Joseph Lombardi later said he was believed to have had at least 10 guns in his hotel room and may have been in the hotel since September 28.
Mr McMahill added: “This is a day I wish I never had to see in my 27 years of law enforcement,” adding that he had never witnessed anything like it in his career.
Long bursts of gunfire came as 64-year-old Stephen Paddock fired indiscriminately towards the 40,000-strong crowd, sending thousands fleeing into the streets in fear as the chaos unfolded.
Despite initial reports suggesting Paddock had been shot by police, Mr McMahill claims he may have turned the gun on himself as police closed in on his location.
He said: “He was shot. I cannot tell you that it was the police that shot him. He may have self-inflicted that gun shot wound. Those details are still emerging.”
He added: “A number of long rifles were in that room. I would say there were at least eight guns up there.
“We continue to receive reports from all of our area hospitals where individuals self-transported themselves. So that number of injured individuals I anticipate to continue to climb over the next couple of hours.”
Swat teams descended on the hotel room where the shooter was positioned, and are believed to have been alerted to his location after the smoke alarm went off as a result of the gunfire.
The latest press release from police reads: “LVMPD SWAT responded to the call, breached the hotel room and found the suspect dead.
“The Clark County Fire Department estimated that approximately 406 people were transported to area hospitals and 50 are dead following Sunday evening’s shooting.”
People have taken to social media to express their outrage at the fact that Mr Paddock was able to get the weapons into the hotel room.
One Twitter user wrote: “The Las Vegas mass shooter was picking his victims at random from a hotel room. America needs to urgently reform its gun laws.”
Another added: “Las Vegas My god 50+ now! Just how easy was it to take a gun into a hotel & Fire at defenceless people!!”
Nevada gun laws are among some of the most relaxed in the US. People are allowed to carry weapons and do not even have to register themselves as owners.
Background checks are done when people buy guns from stores but there are no requirements for buying and selling guns privately.
There are no limits on purchasing ammunition and no bans on automatic or semi-automatic firearms.