Stephen Grammauta and Joe Cahill being the killers came from a. small time blogger who found an old memo, most of which contradict one another. Since Grammauta had become popular on sites like this due to how old he was and speculation on weather or not he was still alive it was picked up by Gerry Capeci for a Gangland story. When Gambino was popular in the early 1970 time period he was blamed, same for Crazy Joe Gallo. We will never know for certain. I'd like to see what Massino and Gravano heard, also Cafaro since he was in that family. None were made at the time Anastasia was killed, but they may have heard from the most reliable of sources the true killers. I think that it had to come from inside the Gambino's or a war would have broken out.