Security Footage Shows Las Vegas Shooter Falling in Casino in 2011

Las Vegas shooter Stephen Paddock had no criminal record prior to his attack from Mandalay Bay on Sunday, but the 64-year-old filed an unsuccessful lawsuit against another Nevada casino in 2014.

Security video from the Cosmopolitan shows Paddock slipping and falling to the ground on Oct. 30, 2011, as he was walking toward a high-stakes area of the casino. He told staff he had slipped in a puddle of liquid and was given medical attention in a separate room of the hotel before being taken out on a gurney.

In 2012, he sued the casino, initially asking for $100,000, the hotel's attorney Marty Kravitz told NBC News. He claimed he sustained a hamstring tear and a sprained wrist as a result of the fall, as well as elevated blood pressure.

The case was scheduled for a civil trial, but instead went into arbitration in 2014.

According to documents outlining the arbitrator's decision, Paddock alleged he incurred more than $32,000 in medical bills and wanted an additional reward for pain and suffering.

The hotel maintained that Paddock had failed to prove negligence because "there was no actual or constructive notice of any liquid in the area of the sundry shop."

The arbitrator determined that while the video shows Paddock slipping and falling, there was also a custodian who can be seen passing the same spot about a minute earlier, followed by about 20 hotel customers who didn't "appear to have noticed anything on the floor [or] tried to avoid a wet area."

A decision was ruled in favor of the Cosmopolitan and Paddock's allegations of negligence were dismissed.

Kravitz said he first met Paddock when he testified in a deposition for the lawsuit. He said that while he looked "unkempt" and "bizarre," there was "nothing about Paddock that would ever indicate someone who was unstable."

Law enforcement officials and a casino executive confirm that in the weeks leading up to the attack, Paddock was seen in Vegas casinos gambling large sums of money — more than $10,000 a day, a source who read his currency transaction reports told NBC News.

On Sunday, Paddock broke a window on the 32nd floor of Mandalay Bay and opened fire into a crowd of more than 22,000 people. As of Monday night, he had killed 59 people and injured more than 500. Police found him dead in his hotel room from a self-inflicting gunshot wound an hour after the attack.