Interfering with custody is a crime in Indiana

Non-custodial parent does not return the child to the custodial parent. Custodial parent goes to the police. The police tell her that this is a civil matter and they can do nothing. Calling the problem a civil matter is only half correct. The non-custodial parent may have also committed a crime.

Indiana criminalized interference with custody years and years ago (IC 35-42-3-4). The non-custodial parent commits a Class D felony if the child removed is between age 14 and 18. If the child is under 14 years of age, the crime becomes a Class C felony. The statute reduces the crime to a misdemeanor so long as the child remains in the State of Indiana:

(b) A person who with the intent to deprive another person of custody or parenting time rights:
(1) knowingly or intentionally takes and conceals; or
(2) knowingly or intentionally detains and conceals;
a person who is less than eighteen (18) years of age commits interference with custody, a Class C misdemeanor. However, the offense is a Class B misdemeanor if the taking and concealment, or the detention and concealment, is in violation of a court order.

Yes, the divorce court has its own remedies but those take time. On a Sunday night at 6:30 pm when the custodial parent finds out that the non-custodial parent will not return the child, the courts are not open. Many problems might be solved quickly and simply by a police officer who knows the law. That leaves to the divorce court (or the paternity court) the task of solving the big problem of modifying visitation.