Those Metrobus ads scheduled to appear on Washington, D.C., buses next week are backed by a couple of somewhat shadowy groups.

The group officially behind the ads, which thank former National Security Agency contractor Edward Snowden for leaking official documents, is the Partnership for Civil Justice Fund.

The PCJF is run by two people, Carl Messineo and Mara Verheyden-Hilliard, who are each paid $130,000 annually for their work as, respectively, treasurer and executive director, according to the group's most recently available IRS 990 tax return, for 2011.

The two are among the organization's nine full-time employees and are described as having founded the organization in 1994.

Although it filed its 990 as a 501(c)(3) non-profit educational foundation, PCJF describes itself in that document as having two equally important purposes: litigation on behalf of civil liberties and public education on behalf of civil liberties. The Metrobus ads fall under the second category.

On the litigation side, PCJF is perhaps best known for settlements it has won on behalf of anti-globalization protesters in Washington, D.C., and New York.

The group received more than $1.7 million in "program services revenue," which presumably represents legal fees gained in litigation settlements.

Unlike many other public interest litigation outfits, PCJF has few charitable donors. The group listed $57,075 in contributions for 2011.

Of that total, $50,000 came from one donor, the Warsh Mott Legacy Foundation in Freestone, Calif. The same donor has given PCJF a total of $135,000 in other grants since 2009, according to donor records.