Yup. They already have enough by their visual confirmation of what happened. They saw what he did. And honestly, if you are willing to 'let it slide' and not hold him accountable you are just encouraging him to repeat this dismal type of behaviour. You already said he has 'Priors' so this is not a first time event.
You must understand that the legal process is individual-specific. This means that if you weren't the one who was charged and you aren't a witness, you are not required at any stage during the process. An attorney would be best laced to advice you on this.