[Cr3aTor]

I need a help and a guidance on finding out the true owner of a website

You're generating too much energy on the website, rather than other means of Information gathering.

If there's a contact form, use It to make an Inquiry and receive a response via email thereafter. Have a look for Identifiable Information In the email address Itself, the contents of the message received, Inspect the email header for timestamps, IP address etc, perform a reverse email lookup, view the email's recovery options for any cell phone numbers linked, check the email address against all major websites for further Info and the list goes on.

^^^ Pretty much
Once you find his identity it's pretty much game over, you can see what is he interested in, family members, where he works, etc and then SE him.