Columbine, Fort Hood, Aurora, Orlando, Virginia Tech, Sandy Hook, and now Las Vegas.

America once again this week broke a record for the most number of people killed in a mass shooting.

My guest today, Dave Cullen, has been writing about these kinds of tragic shootings for almost two decades.

He's the author of the book Columbine, which he spent

10 years reporting and writing, which tells the story of that fateful day in 1999

at a Colorado high school. Dave joins me today to explain why these devastating shootings keep happening in America,

the kinds of people who decide to murder innocence in such cowardly ways, and why he thinks that

eventually these mass shootings could stop happening altogether.

Thanks so much Dave for joining us.

So, you know, this week I woke up as most Americans did and you looked at my phone and there had been yet another mass shooting in America

You've been you know you wrote the book Columbine, you've been writing about this issue

for almost two decades now.

Do these things still shock you?

Yes, in some ways, the magnitude of this did. In fact, oddly enough, you know, I told a friend,

I had trouble getting my arms around this because it was it was too much I couldn't even

conceive when we had over 500 people injured I mean I couldn't even picture that

uh... although probably i guess i didn't want to picture that i kind of refused

but yeah it's still it's still horrifying

to see to you uh... the book that you wrote on coline, you spent, how many years did you spend reporting that?

Well, 10, 10 on the first edition, and then I've sort of kept up in another six years to the expanded edition.

So do you think that part of

part of what we see in these mass shootings is a result of the mass shootings before

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