Please cite a reputable source for that assertion.
TIA
I meant that as a joke, but if you go to Wikpedia’s “June 1962 Alcatraz escape attempt” page, they summarize the reports and name a few television programs that have examined the question. The 2015 History Channel documentary entitled “Alcatraz: Search for the Truth” was probably what I saw, but once again, I wasn’t being that serious.