LAS VEGAS (AP) — The high-stakes gambler responsible for the deadliest mass shooting in modern U.S. history sought notoriety in the attack but left his specific motive a mystery, the FBI said Tuesday as it concluded the investigation of the 2017 massacre that killed 58 country music fans.

While the agency found no “single or clear motivating factor” to explain why Stephen Paddock opened fire from his suite in a high-rise casino hotel, Paddock may have been seeking to follow in his father’s criminal footsteps, the FBI said.