One unsubstantiated complaint in five years hardly constitutes a pattern of abuse.
And the allegation holds more weight than the outcome of the investigation. But, inmates never lie.
Whether this happened or not the murder of Tyre is all on film.
It’s hard to see what defense can be mounted against the charges.
Even if Tyre was a criminal (he had no criminal history) they can’t justify hitting him over the head with a baton as they held him up to beat him more.