From the New York Times:
[W]hat started as a routine arrest then took a fatal turn. As the officers were about to drive Mr. Carter to jail, they found him slumped over, his hands still cuffed behind his back, drenched in blood. According to the police report, he had fatally shot himself in the head.
In the weeks since the death of Mr. Carter, 21, heavy scrutiny has fallen on the police and their procedures, and calls for justice have lighted up Twitter and Facebook.
The police say Carter was searched twice before he was handcuffed and placed in the police car, so one question is where did the gun come from? Another question is why Carter would want to kill himself (and in these circumstances)?