The two were introduced by O'Brien's mother Sylvia in 1943. 

Jimmy Hoffa

James Riddle Hoffa (born February 14, 1913; disappeared July 30, 1975, declared dead July 30, 1982) was an American labor union leader who served as the President of the International Brotherhood of Teamsters (IBT) from 1957 until 1971.

• http://en.wikipedia.org/wiki/Jimmy Hoffa
• Page 64 - Goldsmith, J., 2019, In Hoffa's Shadow: A Stepfather, a Disappearance in Detroit, and My Search for the Truth: Farrar, Straus, and Giroux, New York, 354p.