After a tragedy like the one that happened Sunday, the big question is often: Why?
Why would someone open fire on fellow humans in an effort to kill as many people as possible?
Christian Jaworski has been working to answer that question. He's a professor of sociology at the College of Southern Nevada. He and a colleague are working on a book about mass shooters.
He said although Stephen Paddock was older than most mass shooters, he does seem to fit the characteristics of other mass shooters, including isolation from family and friends, and an estrangement from the community.
Jaworski also said mass shooters are very angry, and angry towards society as a whole. They usually choose targets that are public places or events like a shopping mall, a movie theater or a concert.
He also said while there might be a randomness to the site selection, the actual planning of the shooting is meticulous.
"Once things are in motion these people are very deliberately planned, very cold, very calculated, very premeditated," he said.
He also said there is usually isn't an event that makes a person "snap," but rather there is a constant and growing level of stress and strain that eventually comes to a head.
Jaworski was quick to note that not a lot is known about Paddock's personal life at this point, but it does seem that he fits closely with other patterns of mass shooters.
Jaworski said he wouldn't be surprised if a manifesto written by Paddock was discovered soon.
Christian Jaworski, mass shooting expert, College of Southern Nevada