A convicted killer was arrested after he confessed to savagely stabbing a Bronx grandmother over $80, police said yesterday.

Tyrone Ragland, 50, admitted he was high on crack when he started arguing with Ethal Parish, 70, over cash he claimed she owed him, police said.

On Jan. 5, Parish’s son discovered his mother’s body in her Tremont apartment.

Ragland, who served 15 years in prison for manslaughter, was arrested Tuesday.