Special Agent Leroy Jethro Gibbs,Dr. Donald "Ducky" Mallard
In "Hiatus (Part II)" Jenny tells Dr. Donald "Ducky" Mallardwho 
apparently never knewthat Shannon had witnessed a murder of a Marine at 
Camp... [DOC] [TLE] David McCallum - Wikipedia [PAR] David Keith McCallum, Jr. (born 19 September 1933) is a Scottish actor and 
musician.