The high-roller gambler who opened fire on concertgoers on the Las Vegas Strip had lost tens of thousands of dollars while gambling weeks before the mass shooting and was upset about how the casinos had treated him, according to FBI documents made public this week.
The documents reveal the strongest indication of a motive for the deadliest mass shooting in modern American history. They paint a detailed account of gunman Stephen Paddock's final days before the Oct. 1, 2017, mass shooting that killed 60 people and injured hundreds more.
