I struggled with this questions myself. I came to the same conclussion that men are free to choose. You have the choice to believe in God or not, to look for help or not, to... you get the picture. God did not make your perp do what he wanted to it was his own choice.
Why did God allow it? I do not know but I think it comes back to the freedom to choose.
In my own situation I must confess that had it not been for my realtionship with God - and I am not referring to any religious movement - I would not have survived. I tried commiting suicide more times than I care to remember. In that sense I feel God did not allow it to be succesfull. Just think of the devastation it would have caused the family left behind.
Somebody once asked me what would I do if the same thing happened to one of my boys and I replied that I would be furious and cry for my boys sake. He then replied that in that case don't I think that God is also furious and cried for what happened to me - and in this case to all of us?
I find my strength of working through my issues with Him and I believe I found this site due to Him as well as I have been praying for a long time to get help from people that understand.
I hope I did not offend anybody but this is what I feel and I will not deny my feelings any longer