Manuel and his wife Sandra have been separated in fact for five years. Their two children, Paolo (10 years old) and Maria (8 years old), have been living with Sandra. Manuel filed a petition for habeas corpus under A.M. No. 03-04-04-SC (Rule on Custody of Minors and Writ of Habeas Corpus in relation to Custody of Minors) before the Regional Trial Court (RTC) of Pasig City, seeking to compel Sandra to produce the children and to award him custody. In her return, Sandra alleged that the children are not illegally restrained but are in her care pursuant to an amicable settlement they executed before the Barangay Lupon, which awarded her temporary custody. Sandra moved to dismiss the petition on the ground that Manuel's proper remedy is an action for custody under Rule 99 (Adoption, Guardianship, and Custody of Children) of the Rules on Special Proceedings, not habeas corpus. Manuel countered that habeas corpus is the proper remedy because he is being deprived of his parental right to custody and his children are being illegally restrained. Is the petition for habeas corpus proper? Explain your answer. (Bar 2026 Syllabus)