RJ Cipriano said the casino bosses would never add metal detectors as it could be annoying for the high rollers who spend huge amounts of cash there.
He has now slammed casino bosses and blamed them for the horror atrocity over their lack of security checks.
Speaking to the Sun, he said: “Since 9/11 I’ve been telling casino executives – presidents and Vice Presidents of the major casinos in Vegas that they have a security issue.
“I told them people were coming and going as gamblers and walk into casinos with money, drugs, guns, knives and no one is checked.”
He said a simple metal detector could have prevented the tragedy as the guns would have set off alarms.
The attack has left at least 59 dead and more than 520 injured.
The shocking loss of life makes this gun rampage is the worst mass shooting in US history, eclipsing last year’s massacre of 49 people at an Orlando night club by a gunman who pledged allegiance to Islamic State militants.
Mr Cipriani added: “I guarantee you the bell hops would have carried the guns up to his room on the 32nd floor. 10 rifles and ammunition is a lot of luggage – it should have set off alarms with security but they turn a blind eye.”
He revealed that the shooter was a known gambler in Sin City and had a $50,000 credit line.
Stephen Paddock, 64, opened fire from his hotel room on the 32nd floor of the Mandalay Bay Hotel, where he had been holed up since Thursday September 28.
Officers found an arsenal of 23 guns in the hotel room, some of which were fitted with scopes.
Paddock also had two “bump-stocks”, devices legal in the US which effectively turn semi-automatic rifles into automatic machine guns.
The killer was a multi-millionaire real estate investor and former accountant, according to his brother.
He was not known to police, and had no criminal history except a routine traffic violation.
In a general statement a spokesman for MGM resorts said: “We are heartbroken for the victims, their families and our community.
“Our primary focus and concern in the hours since the shooting has been cooperating with law enforcement and taking actions to support the victims and their families, our guests and employees.”
MGM have been approached for comment about the claims.