FOUND! When I was in San Francisco recently I looked in the library as the archives of the SF Examiner, and found this very interesting story from Nov 15, 1953. It mentions the polygraph machine (or lie detector) that Oakland Police had recently bought, yet was so far unused – including for Johnny Warren’s examination which * NEW INFO * happened at Berkeley.

The green-colored Keeler polygraph machine belongs to the Baltimore PD, and is dated 1955. The one underneath that is from 1963 – it was used to interrogate Jack Ruby, the man who shot Lee Harvey Oswald in the wake of the assassination of JFK.