Who is Father Hart from A Great Deliverance and what is their importance?

Father Hart is the parish priest of St. Catherine's Catholic Church in Keldale, Yorkshire. Father Hart discovers the decapitated body of William Teys in the barn at Gembler Farm. Father Hart has been hearing William Teys' confessions for years. Because of the seal of the holy sacrament of confession, however, Hart is prohibited from telling anyone about Teys' molesting his daughters. Father Hart knows the truth about the baby discovered in Keldale Abbey and the epitaph he chooses for the unknown baby's headstone is meant to be a clue to anyone who cares to investigate the baby's death more closely.