The Writ of Habeas Corpus demands that requires a prisoner must go before the court to determine if there is lawful authority to detain the prisoner. A Writ of Habeas Corpus is a motion which is filed most frequently to ensure that a Defendant's imprisonment or detention is not illegal.Who May Use This Form. What is "habeas corpus"? "Habeas corpus" is a Latin term meaning "bring us the body. This Chapter explains the writ of habeas corpus and lays out the procedures you will need to follow to petition for the writ. The "Great Writ" of habeas corpus is a fundamental right in the Constitution that protects against unlawful and indefinite imprisonment. 1 (The term "federal law" includes not only federal statutes, but also U.S. treaties and the. A federal petition for habeas corpus is filed after a conviction and sentence in state court, and after appeals in state court. Petition For Writ Of Habeas Corpus By A Person In State Custody Pursunat To 28 USC (Non Death Penalty) Form.