On one of the documents which McNeill is photographing,only shown briefly,there appears to be the real name of the imprisoned man, with a line run through.You can see "Joe Ma.....". It would require stopping the film and examining it closely, since it is in handwriting, to be sure. Since I don't have a copy of the movie I can't tell myself, but it might be interesting for someone who has a copy to check.
shareYou are correct about the name of the actual person. I worked with his son (born after release from prison). He confided in me about his father and let me look at letters sent by the reporter to the family during the filming. The reporter was technical advisory for the film. I recall he especially wanted the family to know that the mother was portrayed in a very sympathetic way by an excellent actress.
I was very touched that the son trusted me enough to share that with me.