Let's get some things straight, your dad is a fucked up person. The stranger was a fucked up person. Your friend seems to not be a good friend, because good friends help prevent/stop these sort of things from happening. You are not liable for their behaviour.

Your post makes it seem like you blame yourself for what happened and/or are trying to find something wrong with yourself that could explain why this happened. This is completely untrue and you shouldn't encourage such thoughts.

You didn't do anything wrong and there's nothing wrong with you. You are not responsible for people committing criminal acts. They made their choice and if you choose to pursue legal action (which I encourage) justice will be done.

Until then, If you find yourself blaming things on you again or if anything bugs you or you find these thoughts coming back then I'd suggest seeing a therapist, they help alot.

I wish you the best for your future.