Did he pose as you to get commissioned work?
Did you hire him, based on falsified credentials?
Did he deliver art from another artist pretending it was his?
Did he hire you as an artist, take some pages and then disappear, never paying you a penny?
Then it is time to get in touch. Things are happening. Legal people are being consulted in and around Sacremento, California as well as the FBI.
Email your details and your case study to firstname.lastname@example.org.