If there is some risk that your son could be charged - as it appears that there is - you would be wise to consult with a criminal defense attorney. The attorney can ask around without stirring things up what may be coming. Then, if charges are filed, your attorney can defend your son, seek some con-conviction outcome.
The Trooper just investigates. The prosecutor decides if charges should be brought.
We do not have a client/attorney relationship until you make an appointment, we discuss your case face to face, I accept a retainer, and we explictly agree to enter into representation.
Your son certainly faces criminal exposure and it would be prudent to retain counsel for him at the earliest possible juncture. Do not allow him to speak to the police (or anybody else like the school principal) for any reason, not even to proclaim his innocence. If he makes an admission to the police, he could deprive himself of a possible theory or theories of defense, and the police are only going to try to collect evidence to use against your son. He should also have no contact with the alleged victim in the case, either face to face or online. If the state seeks to charge you son, and the facts alleged support a misdemeanor rather than a felony, then your son will have a clerk's hearing before any charges issue. It is helpful to have an attorney at the clerk's hearing, preferably someone who has experience with juvenile delinquency and school matters.
Dominic Pang (617-538-1127)
This is a time that you and your son should be careful. Even if invited by or pressured by the school to tell his side of the story, he should respectfully decline to do that. He may eventually be charged in juvenile court and if found responsible, beyond a reasonable doubt, he will be adjudicated delinquent. Therefore, as the other attorneys mentioned, he should not speak about the incident with anyone.
He may face suspension or school expulsion. It sounds to me that he may have been teased or taunted and lashed out at the tormentor. You may want to determine from your son whether he has been bullied. For a number of reasons, including his protection, you should consider requesting an evaluation by the school to determine your son's eligibility for special education services.
These are complicated matters and expert advice would be helpful.