Las Vegas Shooting Motive Remains Elusive as Survivors Mark Anniversary

Police crime scene tape marks a perimeter outside the Luxor Las Vegas hotel and the Mandalay Bay Resort and Casino following a mass shooting at the Route 91 Festival in Las Vegas, Nevada. Mike Blake/Reuters

As survivors of the worst mass shooting in U.S. history mark its two-year anniversary, a big question remains unanswered.

The American public is still in the dark why Las Vegas shooter Stephen Paddock opened fire at country music concertgoers at the Mandalay Bay resort on Oct. 1, 2017. He killed 58 people and injured hundreds more.