ProPublica and The Marshall Project won a George Polk Award for the joint investigation An Unbelievable Story of Rape. The piece, which exposed just how disastrously rape investigations can go wrong when law enforcement fails to take victims seriously, was honored in the Justice Reporting category.

Co-written by ProPublica senior reporter T. Christian Miller and Marshall Project staff writer Ken Armstrong, An Unbelievable Story of Rape is the account of an 18-year-old woman who was raped in a Seattle suburb, only to be disbelieved by police and even charged with a crime for false reporting. The attacker went on to rape more women in two states before the vigilant work of two female detectives in Colorado ended the rampage. Told through a mix of powerful narrative and astute analysis, the piece was applauded by the police department that had botched the initial investigation, and several law enforcement agencies have requested permission to use the article as part of their training programs. Last month, it was named a National Magazine Award finalist.

This marks the fourth Polk Award for ProPublica, which received one in 2010 for Abrahm Lustgarten’s series on the dangers of fracking, as well as two in 2011 in recognition of T. Christian Miller’s project with NPR on the U.S. military’s failure to treat soldiers who suffered from traumatic brain injuries, and for A.C. Thompson’s collaboration with Frontline and the Times-Picayune on the brutal actions taken by the New Orleans Police Department in the aftermath of Hurricane Katrina.

Also among this year’s winners is former ProPublica reporter Nikole Hannah-Jones, now of the New York Times, for her collaboration with This American Life on the failing, segregated Normandy School District outside St. Louis. The two-part series grew out of Hannah-Jones’ earlier reporting for the ProPublica story School Segregation, the Continuing Tragedy of Ferguson.