First appearance of a Hughes (MD) 500D (model 369) helicopter on Mannix. This same helicopter (N9014F) has had appearances in Airwolf (1984) and Magnum, P.I. (1980) and several other productions at times with different paint schemes.
The hideout cabin is the same one that was used as the location of the Lone Ranger's silver mine. The cabin was located in the Upper Iverson Ranch, before it was bifurcated by the 118 Freeway, in Chatsworth, CA.
Final television role for David Renard (Fr. Francisco). Renard died of a heart attack at age 52 in August 1973. His final film, Hangup (1974), also featured his Mannix co-star Pepe Serna, who played Alphonso, the man who asked Mannix about the reward.