In August, Pringle reported that a Los Angeles local of the Service Employees International Union and a related charity paid hundreds of thousands of dollars to firms owned by the wife and mother-in-law of the chapter's president and spent similar sums on a Four Seasons Resorts golf tournament, a Beverly Hills cigar club, meals at high-end restaurants and a consulting contract with a Hollywood talent agency.
Most of the 160,000 people represented by the local, United Long-Term Care Workers, earn about $9 an hour tending to the infirm and disabled.
Pringle's reporting led to the firing of the chapter president, Tyrone Freeman, and other union officials and prompted ongoing inquiries by the FBI, U.S. Labor Department and Congress.
Subsequent articles detailed allegations that Freeman ordered employees of a charity founded by the union to work on political campaigns despite laws barring such practices and that another related charity reported spending nothing on its charitable purpose for two of its four years.
The awards, now in their 60th year, are among the most prestigious in American journalism. Other winners announced today:
Barry Bearakand Celia W. Dugger -- a husband-and-wife team -- for reporting in the New York Times on the violent repression in Zimbabwe as President Robert Mugabe struggled to maintain a grip on the nation. Bearak, a former Los Angeles Times correspondent, spent five days in jail for "committing journalism," according to the award announcement.
Paul F. Salopek for reporting from the Horn of Africa for the Chicago Tribune on controversial aspects of America's war on terror. Among the places he reported from was Sudan, where he was beaten and imprisoned in 2006, then freed after the intervention of then-Sen. Barack Obama and other U.S. officials.
David Barstow for his two-part series "Message Machine" in the New York Times, which documented a covert campaign by the Bush administration to transform retired military officers working as analysts for television and radio networks into government mouthpieces and "defense industry rainmakers."
Jim Schaefer and M.L. Elrick for investigative reporting for the Detroit Free Press that led to the resignation and jailing of Detroit Mayor Kwame Kilpatrick.
Eric Nalder for reporting in the Seattle Post-Intelligencer that the Defense Department, after conducting little or no due diligence, awarded $1 billion for military housing to a politically connected consortium, resulting in a loss of millions of taxpayers' dollars.
Ryan Gabrielson and Paul Giblin for a five-part series in the East Valley Tribune of Mesa, Ariz., scrutinizing Maricopa County Sheriff Joe Arpaio's campaign against illegal immigrants.
Richard Behar for an article published in the magazine Fast Company detailing the size and scope of China's investment in sub-Saharan Africa.
Susanne Rust and Meg Kissinger for a six-part series in the Milwaukee Journal Sentinel that examined the failure of federal agencies to regulate toxins found in everyday materials, including "microwave-safe" plastics and baby bottles.
Ken Armstrong and Nick Perry for stories in the Seattle Times reporting that at least two dozen members of the University of Washington football team that played in the 2001 Rose Bowl had arrest records.
Scott Pelley, Solly Granatstein and Nicole Young for "The Wasteland," a "60 Minutes" segment reporting on how some American companies that are paid to recycle electronic waste have instead dumped it in China.
Stefan Forbes, an independent producer and director, for "Boogie Man: The Lee Atwater Story," a documentary about the late Republican operative from South Carolina.
Alex Blumberg and Adam Davidson of Chicago Public Radio's "This American Life" and National Public Radio, whose report titled "The Giant Pool of Money" distilled the chain of events that led to the subprime mortgage crisis.
Gay Talese, journalist and author, George Polk Career Award.
The awards are named for a CBS news reporter who was killed in Greece in 1948 .