A Cold Night's Death (1973 TV movie)
Starring Robert (I Spy) Culp and Eli (The Ugly) Wallach
I've just made a personal discovery decades in the making.  I have long had this deep seated memory from when I was a kid of the final scene of some eerie TV movie thriller in which you see a monkey closing and locking the door to a scientist's laboratory and trapping the man to starve to death alone. My eyes were glued to the screen that night. The scene somehow resonated as one of abstract horror in my memory banks, almost a silent scream. Yet I never encountered another person familiar with the tale, certainly no one who could identify the movie for me.
Well, thanks to some spontaneous Google research this evening one of my bucket list of mysteries to solve in my lifetime has been solved.

From Rotten Tomatoes (http://www.rottentomatoes.com/m/a-cold-nights-death-the-chill-factor/ ) 

Movie Info
This talky but ultimately satisfying made-for-TV sci-fi/thriller stars Robert Culp and Eli Wallach as Drs. Jones and Enari, a bickering pair of scientists dispatched to a remote arctic research station to study the behavior patterns in a colony of monkeys after members of the previous research team die mysteriously. Soon, the quarreling scientific rivals discover that the monkeys are not the only ones being observed -- and that the humans have become the subjects of a far more diabolical experiment. Though the plot's ultimate punchline may not seem as clever as planned, the twisted teleplay from Christopher Knopf packs a fair share of surprises and is superior to the usual TV horror fare. ~ Cavett Binion, Rovi

Unrated, 1 hr. 13 min.
Horror, Mystery & Suspense, Science Fiction & Fantasy
Directed By: Jerrold Freedman

Bill Cosby on his friend Robert Culp and their "I Spy" TV series
(2010) Fond remembrance by Bill Cosby of his friend Robert Culp, recently deceased after a fall near his home.
(http://www.cnn.com/2010/SHOWBIZ/Movies/03/24/obit.robert.culp/ )

Robert Culp is asked about Bill Cosby and "I Spy"