Wow, it sounds like he admitted to it on a talk show at least 7 years ago, and wrote about it in a book [0]! Can't believe it took this long.

[0] https://www.youtube.com/watch?v=x3uoB8zvLdI

edit: just watched the youtube video in full, and it isn't an admission. It's just discussing the shooting in general, and he puts blame on others.