Who was the arresting officer? Isn't that the responsible party until they find out who actually broke his neck?
It's like a chain of custody, but without the documentation. As he gets handed from the lead arresting officer (there was more than one but unlike fighter pilots they do not split arrests) to the transport officer to the <insert magical functionary here> to the intake officer to the jailer each one assumes responsibility for his care and custody.
One of the reasons corrections officers make inmates they are picking up from a local jail is t document the physical condition - nicks, bruises, cuts, contusions, broken necks and the like. Jailer signs off, admitting the "inventory" was correct. Then they'd do it over again when the inmate arrived at the prison reception center. I've heard cops state that they don't have the time to go through all that. Maybe after a certain number of cops who lost their qualified immunity get both locked up and sued the rest will start thinking they might take the time.
stay safe.