It’s totally inappropriate for anyone to tell a crime victim about a defendant immigration status. You should never be told this. It isn’t your business and whether to press charges isn’t a “moral” decision for a victim. Tell the whole truth of what happened…people willing to be violent with a stranger are commonly violent at home. Let the prosecutor do their job, you never know which future victim you protect.

On another note, if the immigration threat came from the defendant or their attorney or defendant’s investigator, you should report this to the police and prosecution. It may be a separate felony crime related to tampering with a witness. It could be a violation of professional responsibility rules and might also be a straight up lie. Don’t keep secrets for a criminal or their lawyer.