The Hague Convention on International Child Abduction sets out standards for what is needed to apply for a return order of a child that is a victim of parental abduction or who has been wrongfully withheld by a non-custodial parent. Those standards are set out in Article 8:
Any person, institution or other body claiming that a child has been removed or retained in breach of custody rights may apply either to the Central Authority of the child’s habitual residence or to the Central Authority of any other Contracting State for assistance in securing the return of the child.
The application shall contain –
a) information concerning the identity of the applicant, of the child and of the person alleged to have removed or retained the child;
b) where available, the date of birth of the child;
c) the grounds on which the applicant’s claim for return of the child is based;
d) all available information relating to the whereabouts of the child and the identity of the person with whom the child is presumed to be. The application may be accompanied or supplemented by –
e) an authenticated copy of any relevant decision or agreement;
f) a certificate or an affidavit emanating from a Central Authority, or other competent authority of the State of the child’s habitual residence, or from a qualified person, concerning the relevant law of that State;
g) any other relevant document.
In theory each signatory country has a duty to aid in the return of a child who has been wrongfully withheld or is the victim of Parental Abduction. In the United States that duty is coordinated through the State Department who designates local authorities such as the Los Angeles County District Attorney’s office to aid in the return of abducted children. In reality, many times the victim parent hires private attorneys such as Pisarra & Grist to aid in the process.