Warning against vigilante's and America's posse/lynching system

This movie could be seen as a warning against American's "taking the law into their own hands", or vigilante "justice". The accused is deemed to be innocent until proven guilty. He was not proven guilty. The mother cannot accept that and murders him in cold blood. Apart from the fact that her crime is worse than what he was accused of, in law he was an innocent man. Imagine the irony if the girl woke up from her coma, and said, mum who have shot the wrong man.