[Bubba Ho-Tep]

It has not yet been proven that the police broke his back, intentionally or otherwise.

He was able to run until arrested. After he was arrested, his neck was broken.

Was he alone?

Just him and the police.

Or was he a Crip/Blood wannabe thrown in with one or more of the otherclan and assaulted?

No. Grey was complaining of injury before the transport stopped and loaded another arrestee, who was separated from Grey by a metal barrier.

Did the vehicle hit one of the numerous potholes (not repaired because the cops can't spare the manpower to protect the repair crew at work)?

Have you ever, in your entire life, heard of someone breaking their neck because their car hit a pothole?

[JimRed]

Was he alone?

Just him and the police.

Grey was complaining of injury before the transport stopped and loaded another arrestee, who was separated from Grey by a metal barrier.

As of now, the Washington Post is reporting that Gray was trying to injure himself according to that other arrestee.