Can Google Alerts Help Find Killers?

By now we've all read the story about the guy who kept a web page about years of rejection and his plans to kill himself and others. And it made me think, doesn't the FBI or somebody track the internet for things like that? Can't they just setup a Google Alert for some phrase like "I am going to kill?" Or certainly they have even more advanced techniques for that.

Or can't the people that manage the main blog sites like blogger and wordpress do that?

So just to check things out, I went to google today and did an advanced search on the words "I am going to kill". I got 121,000,000 hits. I changed it to search for the exact phrase "I am going to kill" and came back with 2,310,000 hits.

I changed it to just search for that phrase on blogspot and got 118,000 hits but only 3,860 on wordpress.

Kind of scary, isn't it?