A week after a gunman used the 32nd floor of a Las Vegas hotel as a hunting perch to kill 58 people in what is the deadliest shooting rampage in modern U.S. history, casino magnate Steve Wynn says the gunman was known to staff, seemed like “a rational man,” and that beefing up security, re-training staff and implementing strict “do not disturb” rules are key to keeping visitors safe.

Wynn, the billionaire CEO of Wynn Resorts, in an exclusive interview with “Fox News Sunday,” said he reassessed his casino’s security in 2015, when he developed a high-level counterterrorism program.

“I got every consultant and adviser I can think of to come through from Ray Kelly to the people from Seal Team 6. It took us from Thanksgiving until May to develop and institute and recruit a program of counterterrorism and it will be two years this May,” Wynn told "Fox News Sunday" anchor Chris Wallace.

“Basically we had to recruit and expand security by tens of millions of dollars to cover every entrance, to retrain the entire workforce -- from housekeeping and room service -- and people are in the tower and observing people. We had to cover every exit and every aspect of the building to see if we could identify and preempt any kind of terroristic or violent action. It is never perfect, of course, but what you can do, to use local vernacular: you can change the odds,” Wynn said.

The Las Vegas gunman, Stephen Paddock, reportedly was holed up in his suite at the Mandalay Bay for three days, instituting a type of “do not disturb” policy that Wynn says would have alerted his Wynn Resorts staff to investigate.

“We also have rules about do not disturb,” Wynn said. “If a room goes on do not disturb for more than 12 hours, we investigate. We constantly -- we don't allow guns in this building unless they're being carried by our employees and there's a lot of them. But if anybody's got a gun and we find them continually, we eject them from the hotel.”

Wynn also said Stephen Paddock and his girlfriend were well-known to his staff.

“He's been staying in Las Vegas since ‘06. So you know, we're talking about 11 years with his girlfriend or at least in recent years, frequent visitor, once or twice a month, to this hotel and others. The most vanilla profile one could possibly imagine. A modest gambler at least by our standards, you know, nothing serious, paid promptly, never owed any money anywhere in Las Vegas. He didn't fit the profile of a problem or compulsive gambler.”

When asked whether he had a motive regarding Paddock’s murderous rampage, Wynn suggested that his previous behavior suggested the gunman was “a rational man.”

'Every historical review of his behavior indicates that he was a rational man.' — Steve Wynn, CEO Wynn Resorts

“This is a man who behaved rationally, privately, a little introverted, liked to play video poker. But he was a rational man. And every historical review of his behavior indicates that he was a rational man; so was his girlfriend. And yet he prepared over an extended period of time, a totally irrational act.

“Now, this sounds like someone either totally demented -- a behavior which he never evidenced -- or someone who's sending a message. This is a plan. We don't know what that message is or if there is one, but this behavior, according to my employees, is as stunning, as unexpected as anybody, any of them have ever met. And that's the status, you know, that I hear from the sheriff, and watching television that seems to be the moment -- the momentary analysis of this situation. I really don't have anything to add to that.”