Do a WHOIS on the domain name, and send to the e-mail addresses in the WHOIS. All of the e-mail addresses for the site, and the Registrar (usually abuse@...).
If the mail to the site admin bounces, send a new e-mail to the Registrar (e.g. GoDaddy, enom, usually abuse@...). The Registrar is one of them that you originally sent to, in the same WHOIS report.
Registrars are obligated to know who their Domain customers are. I report bounces in a second e-mail, to ALL the remaining. Each is a customer of the others, and they all are on the hot seat.
I also usually do a WHOIS on the "NS.whatever.com", the nameserver, and find their e-mail address as well. The WHOIS should be done on the shortest path, so WHOIS on "whatever.com" not the full "ns.whatever.com". But you can try, and compare results of short and full path.
The DMCA I send is to everyone on the first try, all in the "To:" field, not "Cc:".
I did about 6 Friday night, and got action on most of them by Saturday.
When successful, go back to Google where you found the result listing linking to your content, and file for a removal
https://www.google.com/webmasters/tools/removals?pli=1 From your Google webmasters account.