The study makes for a grim chronicle. On October 23, 2004, Jude and a black male friend arrived at a private party in a white middle-class neighborhood as guests of two white women college students. Shortly after arriving, the four headed to their vehicle, but it was soon surrounded by at least 10 men.

The men accused Jude and his friend of stealing Andrew Spengler’s police badge, and all four were pulled from their truck. Jude’s male friend had “his face slit with a knife” and escaped, according to the authors. Jude suffered blows to his face and torso; his arms were pinned behind his back; he was kicked in the head; an officer stomped on his face “until he heard bones breaking;” he was picked up and kicked in the groin so hard “his feet left the ground;” he had a pen inserted deep into his ear canals; his fingers were “bent back” until “they snapped;” before finally being left naked from the waist down on the sidewalk in a pool of his own blood.

Jude’s story would not become public until months later when the Milwaukee Journal Sentinel published a report on the incident on February 6, 2005, and recounted the police cover-up that had followed. Black residents protested almost immediately, demanding action from the district attorney. A month later, nine officers were dismissed. Spengler and two others were tried and acquitted by an all-white jury. Protests ensued again. A federal investigation led to the conviction of seven of the officers involved.

“Once the story of Frank Jude’s beating appeared in the press, Milwaukee residents, especially people in black neighborhoods, were less likely to call the police, including to report violent crime,” David Kirk, one of the authors of the report, said in a statement. “This means that publicized cases of police violence can have a communitywide impact on crime reporting that transcends individual encounters.”

A total of 22,200 fewer calls were made to 911 during the year following Jude’s beating, according to the researchers, with over half of that loss (56 percent) happening in black neighborhoods. The authors of the study see the significant decline as worrisome given how heavily police work depends on resident-initiated interactions, such as calling the emergency line. “Police work of every kind relies on citizen participation, especially reports of law breaking … If police misconduct lowers crime reporting throughout black communities, it directly threatens public safety within those communities, many of which already have high levels of crime,” the authors concluded in the article.

To test their theory that police brutality makes black Americans less likely to contact police, the authors also analyzed the impact of other highly publicized incidents of violence against black men by law enforcement, including two that happened outside of Milwaukee. They looked at the killing of Sean Bell in Queens, New York in 2006, the assault of Danyall Simpson in Milwaukee, Wisconsin, in 2007, and the killing of Oscar Grant in Oakland, California in 2009. Of these three, only the latter did not trigger a drop in calls to 911. The data again led to the conclusion that “other local and national cases of police violence against unarmed black men also had an impact on crime reporting in Milwaukee.”