The actress who plays Betty Viati, the doctor's mistress, is not listed in the end credits of the show even though she has a speaking role.
When McGarrett is going over the ballistics report with Doc. Bergman, the doc mentions that one shot was fired against Mrs. Southmore's head. McGarrett then mentions "coup de grace". This is a French term for "the kill shot", usually the last shot fired to make sure a victim is dead.