banana, I think you are barking up the wrong tree in your search for God.
I'm familure with all the agnostic agonizing over evidence, proof, signs, etc., in which one seeks irrefuteble proof of the existance of God. It just isn't there.
For me, it all boils down to: Do you want to believe in God or don't you?
Personally, I do. I refuse to believe that our existance has no meaning. In my belief, we are very, very small, and God is very, very big in scope. We cannot understand God. Our suffering is temporary, and in the backdrop of eternity, unimportant.
Whether you consider this an act of will or an act of faith, thats what it comes down to: Do you or don't you want God?
If you do want God, you have an answer to your question: Of course this murder is in God's plan.