The Washington Post suspended one of its most seasoned reporters Wednesday after editors determined that “substantial” parts of two recent news articles were taken without attribution from another newspaper. Sari Horwitz, longtime Post investigative reporter, was suspended for three months for plagiarizing sections of stories that first appeared in the Arizona Republic. The stories concerned the investigation of...Jared Lee Loughner... Horwitz copied two paragraphs from a Republic story ... when she wrote an article that was first published on The Post’s Web site March 4. A second story...included 10 paragraphs from a Republic story about a search of Loughner’s home....