GREENSBORO, NC -- Police say the man who killed 58 people and wounded at least 515 at a Las Vegas concert was a retiree with no criminal history in the Nevada county where he lived. The brother of 64-year-old Stephen Paddock said he's "completely dumbfounded" by the shooting at a country music concert Sunday night, which is the deadliest in modern U.S. history.

Now a nation is trying to understand how this happened once again. Another mass shooting on American soil. People are heart broken, some terrified, others outraged. Dr. David Gutterman, a psychologist stopped by the WFMY News 2 to give advice on ways to cope.