i would imagine the watchtower would prefer the murderer to be disfellowshipped before being reported for the crime. That way they can say he/she is not a jw.
Would a JW accused to be a murderer (in a judicial committee) be reported to the police?
I don`t believe they would report it to the police , as that would likely bring reproach on Jehovah`s name. So I would agree with what stan livedeath has said ,they would DF him or her and absolve themselves from any connection to the crime.They can say he or she is not a JW .
If a person confessed to the elders, that would be privileged, and the elders can't report it.
If a person has evidence that someone else committed a crime, that one might go to the elders in an effort to keep the congregation clean because that person does not trust the outside world.
But the congregation should not be involved in such matters.