The man who killed 58 people at a country music festival in Las Vegas last month had been depressed after losing a significant amount of money in the past two years and that may have been a “determining factor” in the worst mass shooting in modern U.S. history, the city’s sheriff said.

Gunman Stephen Paddock, a 64-year-old high-stakes gambler and real estate investor, had lost a “significant amount of wealth” since September 2015, which led to “bouts of depression,” Clark County Sheriff Joe Lombardo said in an interview this week with Las Vegas news station KLAS-TV.

“This individual was status-driven, based on how he liked to be recognised in the casino environment and how he liked to be recognised by his friends and family,” Lombardo said. “So, obviously, that was starting to decline in the short period of time, and that may have had a determining effect on why he did what he did.”