In this blog, we at The Blacknall Firm will break down the complexities of using habeas corpus in child custody disputes. A writ of habeas corpus is an order from a court to an official to produce an inmate.A writ of habeas corpus is a legal tool that a person can use to enforce a superior right of possession to a child. Learn more about the writ of habeas corpus child custody issues with Bryan Fagan, PLLC. Get expert legal guidance to protect your rights. These are the official forms for use in Family Court proceedings. This guide includes forms and instructions for a letter and affidavit to request that the court register an outofstate custody order in Texas. This Chapter explains the writ of habeas corpus and lays out the procedures you will need to follow to petition for the writ. A writ of habeas corpus stands as a vital legal tool, essential for safeguarding individual rights and averting arbitrary detention. Letter to Register Foreign (Out of State) Child Support Order.