I think it's worth noting that this report comes from the Georgia's GBI, i.e. the same people who are accused of killing the activist in question. The previous report comes from a (nominally) neutral source (the DeKalb County Medical Examiner's office).
In other words: the accused are investigating themselves, and have produced a report that suggests that they were justified in killing a climate activist. I think that's a pattern we'd normally treat with extreme skepticism; it's unclear that GBI has earned an exception to that.
Depending on the investigation's ultimate scope, either the federal DOJ or an independent investigator's office.
(It hopefully isn't controversial to say that, as a general principle, entities in positions of exceptional public trust or interest should not be tasked with enforcing or regulating themselves.)
I’m not sure what an independent investigators office is, but assuming it’s a private firm would you not have the same criticism that it’s not a neutral third party and is biased towards whoever hired them?
What is the role of a state level investigation bureau if not to investigate state-level issues involving state agencies?
I meant something like Washington DC's OPC[1]. Note that these commissions are not themselves perfect; they're typically limited in authority to "recommendations," which the police (or DA) may still ignore.
However, to answer the following (which isn't what I meant, but I think is interesting):
> but assuming it’s a private firm would you not have the same criticism that it’s not a neutral third party and is biased towards whoever hired them?
I think the answer to this is similar to the answer found in arbitration: arbitration is typically performed by a well-known firm, and that firm is obligated through contract to perform fair proceedings. In other words: there are civil penalties on the table if the independent party does not execute their job fairly.
That being said, I think an unrelated but still governmental investigation arm would be sufficient here.
> What is the role of a state level investigation bureau if not to investigate state-level issues involving state agencies?
You can find the GBI's services listed here[2]. They have a lot of responsibilities, most of which aren't tied to investigation of local police. I think it'd even be fair to say that they aren't particularly equipped to investigate local forces.
