What? You mean Sydney? 12 years old + lacking discernment, Chase will basically be acquitted.
The person most qualified to seek revenge is Flynn──the only person who cared about Sydney, but he chose not to do it, even though he had the ability to return to the scene of the crime.
Should Chase be punished? For what? Justice? This is somewhat morally ambiguous. If he were punished, who would be happy? Syd's family doesn't care at all—they didn’t even bother with a simple judicial autopsy, if it really was murder.