Cause of death: acute pneumonia
Ibson Dana Elcar (October 10, 1927 – June 6, 2005) was an American television and film character actor. He appeared in about 40 films as well as in the 1960s television series Dark Shadows as Sheriff George Patterson and the 1980s and 1990s television series MacGyver as Peter Thornton, MacGyver's immediate supervisor at the Phoenix Foundation. Elcar had appeared in the pilot episode of MacGyver as Andy Colson before assuming the role of Thornton.
Source : Wikipedia