You will not likely "authoritatively" find this information without a subpoena issued for pending legal action filed in the state where the domain registrar resides.
Unless you are ready to file suit, or hire a private investigator, you are highly unlikely to find the actual owner of a domain, especially if they ownership is obfuscated.
Just "finding it" on the internet is not likely, and Whois information is frequently unreliable. In many instances, where a proxy service is not shielding the identity and contact information of the underlying domain name registrant, you may discover that the information provided in the WHOIS record is inaccurate or incomplete. Occasionally, if the person violating your rights is naïve or does not care about being caught, the WHOIS record may reveal the true identity and contact information of the domain name owner, but this is rare in these kinds of cases. In the vast majority of cases, it is usually not clear from the WHOIS record who the real person or group behind the website is.
Most companies that do offer privacy services shielding the true identity of the domain name registrant also require the registrant to agree not to use those services in violation of others’ rights, including uses that are infringing, defamatory, abusive, threatening, or otherwise unlawful. Most hosting companies (those that service the website owner by storing the website’s content) have similar terms of service. Many of these services reserve the right in their user agreements to terminate the services or even to disclose the identities of their users if they violate these terms. Still, many of these companies are highly reluctant to provide any information unless required to do so by law. Domain privacy services are particularly loath to provide this information because their business models rely on their ability to keep their customers’ identities anonymous.
It really depends on your reason for wanting to know. Much of the information below is verbatim from an internet lawyer in Arizona, where godaddy is located. It is a good read.
If your goal is simply to prevent use of an infringing domain name, one option is to file an administrative complaint under the Uniform Domain Name Dispute Resolution (“UDRP”) procedure. Another soon-to-be implemented administrative procedure is the Uniform Rapid Suspension (“URS”) procedure. These procedures are governed by rules adopted by the Internet Corporation for Assigned Names and Numbers (“ICANN”), the body that coordinates and controls the domain name system and Internet Protocol (“IP”) addresses.
The UDRP allows the infringing domain name to be transferred to a successful complainant, whereas the URS will be a fast means of stopping registration of a clearly infringing domain name. A UDRP proceeding (and likely a URS proceeding) may be filed against the listed registrant of the domain name, even if that registrant is the privacy company itself. The advantage of these administrative procedures is that they generally work on a set time line and therefore are usually less expensive and faster than asserting claims in court.
In certain cases, claims may be filed against an anonymous person or even against the domain name itself, which is considered intangible property subject to disposition by a court. Although a court proceeding is far more expensive and time consuming than administrative proceedings, filing claims in court allows you to seek damages and injunctive relief such as a permanent injunction against future violation of rights, which would otherwise be unavailable in an administrative proceeding.