I like movies and television shows that involve sinister, influential characters manipulating events and sending other, even more sinister characters out to impose mayhem upon the world. I find such movies and television shows to be very entertaining.
But it's only fiction and I don't take it seriously.
When I was a teenager I saw a movie titled, "Executive Action." It was about a group of fabulously wealthy men who orchestrated the assassination of President Kennedy. I've seen it a couple of times since then and I still find it entertaining, but I don't believe any of it and the reason for my incredulity is simple and familiar to just about everyone.
No one can keep a secret.
We all keep secrets about relatively unimportant, personal matters, especially if they're of a sexual or scatological nature. Secrets involving behavior motivated by a sense of fear or powerlessness are almost impossible to hold inside forever. One of the driving forces behind school shootings is the killer's sense of powerlessness. Someone who's being mistreated or simply being ignored or shunned has an overwhelming desire to correct the problem. And one's sense of powerlessness is not truly compensated for unless everyone knows you did it. What the killer really wants, to paraphrase Eric Harris, is to be respected. Simply killing a bunch of people, or a select group of people doesn't inspire anyone to respect you and treat you better if they don't know who you are.
This is why so many potential school shooters get caught before they shoot anyone. They're not really that interested in killing people. They just want to be treated in a manner more in line with the all too empty rhetoric of a civilized society and they mistakenly believe that the mere threat of committing a media worthy act of revenge will satisfy that need.
There was no conspiracy at Columbine. The fact that two teenagers were able to keep their plans secret for as long as they did is almost unbelievable. Three or more is ludicrous.