ProPublica, a nonprofit news organization, won a coveted Pulitzer prize on Monday for The Deadly Choices at Memorial about controversial deaths at a New Orleans medical center in the wake of Hurricane Katrina.

The article by Sheri Fink, done in collaboration with The New York Times Magazine, marked the first time an online news organization working with a newspaper won a Pulitzer Prize, given to honor journalism, books, drama and poetry.

The website of the San Francisco Chronicle won for editorial cartooning, the first time an Internet-based entry won in that category.

The Washington Post won the most, with four Pulitzer prizes.