Cause of death: fire
John Joseph Edward Cassidy (March 5, 1927 – December 12, 1976) was an American actor, singer and theatre director. He received multiple Tony Award nominations and a win, as well as a Grammy Award, for his work on the Broadway production of the musical She Loves Me. He also received two Primetime Emmy Award nominations. He was the father of teen idols David Cassidy and Shaun Cassidy.
Source : Wikipedia