A writ of habeas corpus is another means to fighting the legality of one's incarceration or proving actual innocence. A writ of habeas corpus refers to a court order that is issued to either an agency or a person who is holding someone in custody.In Texas, the state writ of habeas corpus is a legal mechanism that allows individuals to challenge their detention or imprisonment. An application for a writ of habeas corpus asks a court to overturn your conviction because of a state or federal constitutional violation. The writ of habeas corpus is the remedy to be used when any person is restrained in his liberty. A writ of habeas corpus is a legal order that requires the custodian to bring the detained individual before a court or judge. Let's start with the basics. XXXXXXX and placed him in the custody of the South Texas Detention Complex. This petition, called a writ of Habeas Corpus, is filed in Federal Court (US District Court ) whether you are serving time in a federal or state prison. What Is Habeas Corpus?