Sa Piling Ng Aswang (1995)

A Manila professional determined to unearth the mysterious disappearance of her younger brother. Plagued by guilt over neglecting and ignoring the needs of her brother, she takes a bitter and scary journey to the island of Panay where her brother was last seen. On her way to the dreaded town of Panitan, Maricel runs into a group of students who are on a research project to disprove the existence of witches in that town.

Unfortunately the movie Sa Piling Ng Aswang is not yet available on HBO Max.