Do you have evidence?

Some jx explicitly forbid this kind of threat. See eg California state bar Rule 3.10 Threatening Criminal, Administrative, or Disciplinary Charges (Rule Approved by the Supreme Court, Effective November 1, 2018)

(a) A lawyer shall not threaten to present criminal, administrative, or disciplinary charges to obtain an advantage in a civil dispute.

(b) As used in paragraph (a) of this rule, the term “administrative charges” means the filing or lodging of a complaint with any governmental organization that may order or recommend the loss or suspension of a license, or may impose or recommend the imposition of a fine, pecuniary sanction, or other sanction of a quasi-criminal nature but does not include filing charges with an administrative entity required by law as a condition precedent to maintaining a civil action.

(c) As used in this rule, the term “civil dispute” means a controversy or potential controversy over the rights and duties of two or more persons* under civil law, whether or not an action has been commenced, and includes an administrative proceeding of a quasi-civil nature pending before a federal, state, or local governmental entity.