“My decision will not bring Tony Robinson Jr. back,” he said. “My decision will not end the racial disparities that exist in the justice system, in our justice system. My decision is not based on emotion. Rather, this decision is based on the facts as they have been reported to me.”

Image Officer Matt Kenny will not face criminal charges. Credit... Madison Police Department

Although Mr. Ozanne did not mention either man’s race, he discussed his own identity at some length — the biracial son of a black woman from Anniston, Ala., who, he said, worries that his skin color puts him at risk.

“I am a man who understands the pain of unjustified profiling,” he said, seeming shaken and pausing several times to mop his face with a handkerchief. “I am cognizant of the very real racial disparities and equity issues which exist in this county.”

Outside the courthouse, Mr. Robinson’s grandmother, Sharon Irwin, said she cried when she heard the decision. “There’s just no justice,” she said. “I don’t know what else to say.”

Mr. Ozanne met with family members before revealing his decision, expressing condolences but giving them no inkling of what he would do.