John Carreyrou is an American investigative journalist and author. He is best known for his reporting on the fraudulent activities of the blood-testing startup Theranos, which was published in The Wall Street Journal in 2015. His reporting on the company's fraudulent activities led to its downfall and the criminal prosecution of its founder, Elizabeth Holmes. Carreyrou's reporting on Theranos was the subject of the 2019 HBO documentary The Inventor: Out for Blood in Silicon Valley. Carreyrou has also written for The New York Times, The Washington Post, and The New Yorker. He has won numerous awards for his investigative journalism, including two Pulitzer Prizes, a George Polk Award, and a Gerald Loeb Award. He is the author of the 2018 book Bad Blood: Secrets and Lies in a Silicon Valley Startup, which chronicles the rise and fall of Theranos. Carreyrou is currently a staff writer at The Wall Street Journal.