On a sunny Saturday last April, a small crowd gathered in a Calumet City park to mourn the loss of a black child.

"I want you to realize we have tragedies every day, black families," 58-year-old Steven Watts told the crowd. His voice was worn and somber, barely eclipsing the hum of passing cars. "I saw it. I watched it. And for three years now, this is what I see every single day: I see my son dying. I see his eyes closing. And for what?"

Watts flexed his thumb and forefinger, thinned by an ongoing battle with stomach cancer, into the shape of a gun. It was a crude representation of the scene he witnessed in the basement of his home on February 1, 2012, when Calumet City police officers William Coffey and Robert Hynek shot and killed his youngest child....

Stephon (pronounced steh-FON) had autism. He was diagnosed with Asperger's syndrome—a complex developmental disability characterized by social and communication difficulties, eccentric behavior, and often singular, intense interests—at age nine. People with an autism spectrum disorder are seven times more likely to encounter police than "neurotypical" individuals, or those without developmental disabilities, according to autism experts. Depending on the severity of their disorder, people on the autism spectrum can react inappropriately to police and have trouble following commands.