Reporters Comittee for Freedom of the Press, is a great resource for private investigators to reference local requests for public information.

"The Reporters Committee for Freedom of the Press was created in 1970 at a time when the nation's news media faced a wave of government subpoenas asking reporters to name confidential sources.
One case particularly galvanized American journalists. New York Times reporter Earl Caldwell was ordered to reveal to a federal grand jury his sources in the Black Panther organization, threatening his independence as a newsgatherer.
Caldwell's dilemma prompted a meeting at Georgetown University to discuss the need to provide legal assistance to journalists when their First Amendment rights come under fire. Among those present, or involved soon afterwards, were J. Anthony Lukas, Murray Fromson, Fred Graham, Jack Nelson, Ben Bradlee, Eileen Shanahan, Mike Wallace, Robert Maynard and Tom Wicker.
They formed a committee that operated part-time and on a shoestring (its first "office" was a desk in the press room at the U.S. Supreme Court). With support from foundations and news organizations, the founders built a staff and began recruiting attorneys to donate their services.
In recent years, the Committee has taken the lead in building coalitions with other media-related organizations to protect reporters' rights to keep sources confidential and to keep an eye on legislative efforts that impact the public's right to know. It also has aggressively sought opportunities to speak out nationwide through amicus curiae briefs filed on behalf of journalists.
In the last four decades the Committee has played a role in virtually every significant press freedom case that has come before the Supreme Court -- from Nebraska Press Association v. Stuart to U.S. v. Moussaoui -- as well as in hundreds of cases in federal and state courts.
The Committee has also emerged as a major national -- and international -- resource in free speech issues, disseminating information in a variety of forms, including a quarterly legal review, a bi-weekly newsletter, a 24-hour hotline, and various handbooks on media law issues."


Links: http://www.rcfp.org/