Besides playing Uncle Ben Parket in the Spiderman Movies, I remember seeing him a number of the older movies that I used to watch via Bill Kennedy at the Movies in the late '60s to mid '70s.
Yeah he was, 6 of them, and for exposing a crime committed by a Hollywood boss.
From Wikipedia:
Columbia Pictures Scandal
In 1977, Robertson discovered that his name had been forged on a $10,000 check, although it was not money that was due him. He also learned that the forgery had been carried out by Columbia studio head David Begelman, and on reporting it he inadvertently triggered one of the biggest Hollywood scandals of the 1970s. Robertson was subsequently blacklisted for several years before he finally returned to film in Brainstorm (1983).[7][10] The story of the scandal is told in David McClintick's 1982 bestseller "Indecent Exposure."