Libel/slander/defamation are civil torts or wrongs. Harassment is a criminal act. In NJ, generally, it is an act or series of acts with which the intent is to (seriously) annoy or alarm another. Absent intent, it is legal. Some states hold that if there is any legitimacy to the communication at all that it is a legal communication.

If the police haven't come to you, they probably just want a statement or to ask you some questions because you have been fingered as the possible perpetrator, or at least believed to be involved. You don't have to talk to the police and can stop talking any time you want to. I am not sure if you have a right to have a lawyer present if you are not a suspect. But if you are a suspect, I believe they have to inform you of your Miranda rights.