LAS VEGAS — He was a nocturnal creature who gambled all night and slept all day.

He took Valium at times for anxiousness, and had the doctor who prescribed it to him on retainer.

He wagered up to a million dollars a night, but wandered around glitzy Las Vegas casinos in sweatpants and flip-flops, and carried his own drink into the high rollers’ area because he didn’t want to tip the waitresses too much.

This was Stephen Paddock as he saw himself four years before he opened fire on a crowd of concertgoers, killing at least 58 people in the worst mass shooting in modern American history.

The details are contained in a 97-page court deposition obtained exclusively by CNN. Paddock was deposed October 29, 2013 as part of a civil lawsuit against the Cosmopolitan Hotel, where he slipped and fell on a walkway in 2011.

What otherwise would have been a mundane proceeding offers fresh details about Paddock’s life and habits — for the first time — from the killer’s own mouth. The document has been turned over to the FBI, according to sources.

Kept doctor ‘on retainer’

Paddock’s testimony offers little insight into what could have prompted last week’s attack. He said that he had no mental health issues, no history of addiction and no criminal record.

He said he was prescribed Valium “for anxiousness” by Nevada internist Steven P. Winkler. It was unclear how often he took the drug, but he estimated that he had 10 or 15 pills remaining in a bottle of 60 that were prescribed a year and a half earlier.

Rage, aggressiveness and irritability are among the possible side effects of taking diazepam — better known as Valium, according to a manufacturer of the drug. It is not known when Paddock last took the drug.

The Las Vegas Review-Journal reported that Dr. Winkler prescribed him diazepam in June, based on information contained in Nevada’s prescription drug monitoring database. CNN could not independently confirm that information.

Paddock was asked whether he had a good relationship with the doctor who prescribed him the pills.

“He’s like on retainer, I call it, I guess,” Paddock said of Winkler. “It means I pay a fee yearly … I have good access to him.”

Winkler did not respond to an email or phone call seeking comment for this story. Reporters were turned away by a security guard after seeking access to the gated community where he lives.

In the deposition, Paddock said he had a concealed weapons license in Texas, but, other than that, there was no discussion of guns.

Always on the move

Paddock described himself as something of a rolling stone who split his time among California, Nevada, Texas and Florida, traveling at one point “maybe upwards of three weeks out of a month.”

His de facto home was often one of the casinos, where he stayed in rooms that were provided for free “95% of the time.” Hotels often provide free rooms and amenities to big gamblers to entice them back to their casinos.

At the Cosmopolitan, he said he had opened a bottle of sake in his room, possibly on the night of the incident, but did not drink much.

A lawyer asked him to explain why he would open the beverage but not drink it.

Paddock explained that everything in his room was “comped” or free, “so, yes, I would open all sorts of things.”

“And if you aren’t comped at casinos, you wouldn’t understand,” he added.

He said he wandered about in black Nike sweat pants and had a favorite pair of size 13 black flip-flops — the pair he was wearing on the night of his accident at the Cosmopolitan in October 2011. He was on his way to the high-limit room when he slipped on some liquid and fell. He testified that he hurt his hamstring, which he said resulted in a lingering injury. An arbitrator ultimately ruled in the Cosmopolitan’s favor, according to two sources.

‘I do not do sun’

Some of the testimony centered on his gambling.

He described himself as being, at one point, the “biggest video poker player in the world.”

“How do I know that?” Paddock asked rhetorically. “Because I know some of the video poker players that play big. Nobody played as much and as long as I did.”

At the height of his play in 2006, he testified, “I averaged 14 hours a day, 365 days a year.”

“I’ll gamble all night,” he said. “I sleep during the day.”

Asked if he ever visited the hotel pool, Paddock replied, “I do not do sun.”

Paddock said he rarely drank alcohol when he gambled, because “at the stakes I play, you want to have all your wits about you, or as much wit as I have.”

“Each time I push the button, it will range from $100 to $1,350,” he said.

A lawyer asked how much he could end up betting on a given night.

“A million dollars,” Paddock replied.

“That’s a lot of money,” the lawyer said.

“No, it’s not,” Paddock said.

The deposition also offered some clarity on basic biographical information about the enigmatic killer.

He was “raised mostly in California,” attending high school in the Sun Valley section of Los Angeles and college at what would become Cal State Northridge. He worked for a time as an IRS agent, then began to invest in real estate.

Paddock did not detail the initial source of his wealth. He at times came off as arrogant and sarcastic during the deposition, the transcript suggests.

At one point he was asked whether he was sober on the night of the accident.

“I was my normal happy-go-lucky self,” he said. “Perfectly sober.”