The way Sheldon Haleck’s parents see it, the 38-year-old’s only crime was jaywalking. But that March night in 2015, after Honolulu police found him behaving erratically, they pepper-sprayed him, shocked him with a Taser, and restrained him. Haleck became unresponsive and was taken to a hospital. Before his parents could get from their home in Utah to Hawaii, the former Hawaii Air National Guardsman was taken off life support.

“Nobody’s supposed to die from something like this,” said Haleck’s father, William.

An initial autopsy ruled Haleck’s death a homicide and his family filed a civil lawsuit in federal court against the three officers who tried to remove him from the street. The case should have been “one of the easiest wrongful death cases” to win, said Eric Seitz, an attorney who represented Haleck’s family.

But the officers’ attorneys seized on a largely discredited, four-decade-old diagnostic theory called “excited delirium,” which has been increasingly used over the past 15 years as a legal defense to explain how a person experiencing severe agitation can die suddenly through no fault of the police. “The entire use of that particular theory, I think, is what convinced the jury,” Seitz said.