Police in Iowa fatally shot an unarmed 19-year-old in a pickup truck on the campus of Iowa State University Monday. Tyler Comstock’s father called police after his son took off in the truck following a dispute over his father’s refusal to buy him cigarettes. Police say Comstock rammed a cruiser and refused to turn the truck off. But dispatch audio shows police were twice told to back off. This is the second of two warnings.

Police staffer: “We know the suspect, so we can probably back it off.”

Less than a minute later, a voice announces Comstock has been shot. Comstock’s step-grandfather told the Des Moines Register, “So he didn’t shut the damn truck off, so let’s fire six rounds at him? We’re confused, and we don’t understand.”