Dana Thornton faces a court hearing in Morristown next week at which attorney Richard Roberts will seek to have the indictment thrown out.
The Morris County Prosecutor's Office indicted Thornton last year on one count of fourth-degree identity theft, a crime punishable by a maximum of 18 months in jail if she is convicted at trial.
Thornton, of Belleville, could not be reached by phone Wednesday, but Roberts said the law and Thornton's actions don't mesh.
"The statute as it exists really is aimed at people who actually go into a store with a phony credit card, for instance, and use that number and assume that name while committing a crime," he said. "When you're talking about things that get put on the Internet you're getting into free speech."
Authorities allege Thornton created the Facebook page as if it was made by her former boyfriend, Parsippany police detective Michael Lasalandra, and made disparaging comments purportedly from him. Lasalandra didn't return a phone message seeking comment Wednesday.
The statute says a person is guilty of identity theft if he or she "impersonates another or assumes a false identity and does an act in such assumed character or false identity for the purpose of obtaining a benefit for himself or another or to injure or defraud another."
The Morris County Prosecutor's Office declined to comment on the case.
Jeffrey Pollock, an attorney who recently argued a case before the state Supreme Court that focused on whether bloggers have the same protections as journalists, said the case could break new ground in identity theft law.
He added that Lasalandra might have a strong civil claim for defamation.
"It's an unusual claim because the statements are not being made about him, but indirectly he's being made liable and that impairs his reputation," he said. "It's putting a false statement in writing that reflects on the morality of the person you're talking about."
Roberts said New York recently amended its identity theft statute to make it a crime to impersonate someone by electronic means, but that New Jersey has yet to do so.
"The legislative history of our statute makes no mention of electronic means," he said. "The statute doesn't fit the crime, which we don't even admit was a crime."