'Notebook' director Nick Cassavetes is on the hunt for his 13-year-old daughter, whom he says has disappeared ... and he says it's all a diabolical plot by his estranged wife.
Law enforcement tells TMZ ... Cassavetes filed a police report. He claims Heather Wahlquist has been on the run with Barbie for the last month. He says he has ferociously tried to gain contact with Barbie to no avail ... her phone has been shut off and Heather refuses to take his calls.
Cassavetes has filed a crime report claiming Heather is violating their custody arrangement and has effectively stolen Barbie from him.
Cassavetes tells TMZ, "My 13 year old daughter Barbarella Cassavetes has gone missing, her mother repeatedly ignoring and disobeying court orders and stipulations. Heather Wahlquist is on the run, refusing to let me see Barbie, ignoring mandatory court appearances, and evading law enforcement."
Cassavetes goes on to say ... "We believe her family, grandmother Linda Massad and great aunt Jeanette Massad Anderson have been assisting in hiding Barbie and have also been served ... I don't know if she is okay or not, and I am extremely concerned for her well being."