I am a United State Secret Service Agent and promise you that law enforcement does not work this way.
ALL POP UP WINDOWS CLAIMING SUCH NONSENSE IS A SCAM!!
When we act, we take websites over through the server and provider. AND WE NEVER ARREST OR INVESTIGATE SUCH THINGS UNLESS THERE IS A HISTORY OR PATTERN NOT SINGULAR EVENTS AND NO HISTORY.
Enjoy your porn. We are human and women and men who are normal and realistic. As long as you are not actively seeking, storing and sharing illegal porn (Child and Snuff) Then you are fine. We aren't coming after you. You are ok. Enjoy yourself. Stay away from child porn and snuff porn and everything else is ok, no matter how strange or disgusting to most.