I continue adding new material to The Columbine Guide. I just uploaded Eric Harris' "Hitmen for Hire" school assignment. Eric submitted it in December, four months before the Columbine attack.
This is Eric's business plan for the video of he made with Dylan Klebold, also titled "Hitmen For Hire." It's pretty horrifying in retrospect, though presumably seemed funny at the time.
This assignment include an overview of the product, business organization, plans for fundraising and advertising, etc. You can see the Table of Contents there.
You can read Eric's complete business plan at the link, and watch the video from there as well.
I cover all this in my book, Columbine.