Brave And The Bold #169 December, 1980.

Batman suspects a faith-healer called Angela Marcy from being a fraud and from murder, but Zatanna decides to prove Batman wrong. When the people that have been formerly "cured" by the miracles of Marcy start becoming ill once again, Zatanna admits that there is more than meets the eye and she works with Batman to find the truth behind Marcy's miracles.