Movies You Haven't Seen But Should: The Power

From Wikipedia:

The Power is a 1968 film based on the science fiction novel The Power by Frank M. Robinson. Its protagonist, a researcher named Tanner, discovers evidence of a person with psychic abilities among his coworkers. As he tries to uncover the superhuman, his existence is erased and his associates murdered, until he faces a showdown with an apparently undefeatable opponent.

Produced by George Pal and directed by Byron Haskin, it was substantially changed in the John Gay screenplay, moving the location to San Marino, California, changing most of the characters' names (although retaining the surnames of Tanner, Nordlund, and department head Professor Van Zandt), and eliminating several subplots and characters, presumably to fit the story into a 108-minute film. George Hamilton starred as Professor Jim Tanner, Suzanne Pleshette as his teammate and romantic interest Margery Lansing (Marge Hanson in the novel), and Michael Rennie (famous among science fiction movie fans as Klaatu in The Day the Earth Stood Still) as new government liaison Mr. Nordlund. Otherwise, the story proceeds in a fashion similar to the novel, except for a somewhat different twist to the conclusion.

This somewhat obscure movie is memorable for a number of intriguing scenes, including murder by centrifuge, a seemingly possessed "Walk/Don't Walk" sign, toy soldiers firing with real gunpowder, and winking inanimate objects (the last two also in the novel). The soundtrack also memorably features a beating heart to signal the mind-control attempts and eerie music from a cymbalum (a hammered dulcimer-like instrument) accompanying the more suspenseful moments. The music, written by Oscar-winning composer Miklós Rózsa, actually contributes an amusing fourth wall-breaking moment when Tanner, hearing the haunting tune, seems to expect a new disaster, only to be visibly relieved when he finds a cymbalum-violin duet being performed in the hotel lobby.

And here it is on the IMDB