The practice of giving sedatives to people detained by police has spread quietly across the nation over the past 15 years. The strategy, intended to reduce violence and save lives, has proven deadly, and disproportionate: Of the 94 who died over the past decade; about half were Black. The deaths illustrate an often-hidden way fatal U.S. police encounters end: not with the firing of an officer’s gun but with the silent use of a medical syringe.