Hello and welcome to JustAnswer. Please note: (A) This is general information and is not legal advice. No specific course of action is proposed herein, and no attorney-client relationship or privilege is formed by speaking to an expert on this site. By continuing, you confirm that you understand and agree to these terms; and (B) the site allows experts not to participate in phone calls and I may or may not be able to participate in this feature.I am sorry to hear about this situation.A) This is not a federal offense. How can it be? You did not steal their mail. You did not vandalize their mail or their mailbox. See HERE, generally. Their claim that this is a federal offense is pretty much ridiculous.B) This is not a threat. See HERE for the definition of a threat under PA law. Do you think the county prosecutor is really going to believe that the placing of such a letter constitutes one of the following: (1) commit any crime of violence with intent to terrorize another; (2) cause evacuation of a building, place of assembly or facility of public transportation; or (3) otherwise cause serious public inconvenience, or cause terror or serious public inconvenience with reckless disregard of the risk of causing such terror or inconvenience. I do not think so.C) This is not harassment. See HERE for the definition of harassment under PA law. Is placing a letter in one's mailbox equivalent to one of the following: (1) strikes, shoves, kicks or otherwise subjects the other person to physical contact, or attempts or threatens to do the same; (2) follows the other person in or about a public place or places; (3) engages in a course of conduct or repeatedly commits acts which serve no legitimate purpose; (4) communicates to or about such other person any lewd, lascivious, threatening or obscene words, language, drawings or caricatures; (5) communicates repeatedly in an anonymous manner; (6) communicates repeatedly at extremely inconvenient hours; or (7) communicates repeatedly in a manner other than specified in paragraphs (4), (5) and (6). Of course not.D) The neighbor either (a) overreacted, or (b) is attempting to scare you, or (c) both. Regardless, this really would not be a criminal
matter. Or should not be, rather. They were just trying to frazzle you a bit, and they succeeded. But this is not actionable, arguably.I hope this helps and clarifies. Gentle Reminder: Use the SEND or REPLY button to keep chatting, or please RATE when finished. You may always ask follow ups at no charge after rating. Kindly rate my answer as one of TOP THREE FACES/STARS and then SUBMIT, as this is how I get credit for my time with you. Rating my answer the bottom two faces/stars or failing to submit the rating does not give me credit and reflects poorly on me, even if my answer is correct. I work very hard to formulate an informative and honest answer for you; please reciprocate my good faith.