After you file

Does anyone know if you can turn a custodial parent into the IRS for fraud if they have refused to follow a state court order requiring the parents to rotate claiming the child on taxes? Mother has refused to follow court order, and has instead claimed child every year, refusing to allow father to claim the child on his years.  This has been going on for many years now. How would we go about doing anything about this through the IRS? We are filing contempt charges against the mother for this, but is there anything we can do through the IRS since the court order specifies years each parent is to claim child, and without any prerequisites to do so?