Ricky is right, since McGurn was dead in 1936 and was allegedly ousted from the Outfit a couple of years before that. On top of that, Alex was too young that same year to be riding with Accardo and the rest of the boys, so in plane words that's nonsense and it possibly occurred during the late 1930's or early 1940's.
No it is not nonsense. George, Gus, and Sam Alex brother-in-law Joseph Glimco was in the same crew as Tony Accardo and Vincent Gibalbi that was headed by Frank Rao. Rao handed the contract to Tony Accardo to kill Tommy Maloy who is who rickydelta is thinking of. Accardo and Glimco machine gunned Maloy in his car when they pulled up to him. Gus may have been young at the time, but he was already hanging out with mobsters and they knew the Alexs. The Maloy hit is the first time that can be documented of Vincent Gibalbi having some sort of problem in the underworld as he would have been given the contract instead of Tony Accardo. The Alexs were known to be solid and stand up guys in Chicago even at young ages, as their father Nick was well respected amongst the mobsters.
