Habeas Corpus as Post-Conviction Remedy

Habeas corpus is a post-conviction remedy. The writ of habeas corpus applies to all cases of illegal confinement or detention in which individuals are deprived of liberty. The writ may not be availed of when the person in custody is under a judicial process or by virtue of a valid judgment.
However, as a post-conviction remedy, it may be allowed when, as a consequence of a judicial proceeding, any of the following exceptional circumstances is attendant: (1) there has been a deprivation of a constitutional right resulting in the restraint of a person; (2) the court had no jurisdiction to impose the sentence; or (3) the imposed penalty has been excessive, thus voiding the sentence as to such excess. (G.R. No. 151876, June 21, 2005)