ProPublica announced today that it has hired Ken Armstrong as a senior reporter.

Armstrong comes to ProPublica from The Marshall Project. His series examining how death row inmates have been denied the chance to appeal their convictions in federal court because lawyers missed the filing deadline was featured at the launch of The Marshall Project in 2014. For his collaboration with ProPublica’s T. Christian Miller, about the hunt for a serial rapist, he won the 2016 Pulitzer Prize for Explanatory Reporting.

Armstrong previously reported for the Seattle Times, where he won the 2012 Pulitzer Prize for Investigative Reporting for a series with Michael Berens that showed how the state of Washington steered Medicaid patients and others to a cheap but unpredictable painkiller linked to more than 2,000 deaths in the state. At the Seattle Times he also shared in two staff Pulitzers for breaking news for coverage of a landslide that killed 43 people and the shooting deaths of four police officers.

He has also written for the Chicago Tribune, where his work helped prompt the Illinois governor to suspend executions and empty death row. In addition to Armstrong’s four Pulitzer Prizes, he has been honored with six IRE Awards, a Peabody Award, and the John Chancellor Award from Columbia University for lifetime achievement. His book with Nick Perry, Scoreboard, Baby: A Story of College Football, Crime, and Complicity won the Edgar Allan Poe Award for nonfiction.

“Over his reporting career, Ken has consistently taken on important stories, writing with moral force about people in power and creating lasting impact in the communities he has covered,” said ProPublica managing editor Robin Fields. “We are thrilled to bring his tireless reporting to our newsroom.”

“I’ve been a fan of ProPublica’s for years — the deep reporting, the range of stories, and the bold approach to telling them,” said Armstrong. “I’m so grateful to be welcomed aboard.”