The Washington Post has suspended a Pulitzer Prize-winning reporter for three months for lifting material from another US newspaper.
Sari Horwitz, who won America's top journalism award with a colleague in 2002, was found to have used "substantial" parts of two articles from the Arizona Republic in her stories without attribution, the newspaper said.
The stories involved the January shooting in Tucson, Arizona, that left US Congresswoman Gabrielle Giffords severely wounded and six other people dead, including a federal judge and a nine-year-old girl, the Post said.
In an editor's note, the Post apologized to the Arizona Republic and readers "for this serious lapse.
"It is the Post's policy that the use of material from other newspapers or sources must be properly attributed," it said.
Post executive editor Marcus Brauchli told the newspaper no other instances of plagiarism by Horwitz had been found in a review of her work this year.
The Post said Horwitz began working at the newspaper in 1984 and won a Pulitzer with a colleague in 2002 for reporting about the deaths of foster children while in the care of Washington child-welfare authorities.
It said she was also a member of reporting teams that jointly won Pulitzers in 1998 and 2007.
Horwitz apologized in a statement published by the Post.
"I am deeply sorry. To our readers, my friends and colleagues, my editors, and to the paper I love, I want to apologize," she said.
"Under the pressure of tight deadlines, I did something I have never done in my entire career. I used another newspaper's work as if it were my own. It was wrong. It was inexcusable. And it is one of the cardinal sins in journalism."
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