Other mistake: In the scene where John and Tommy are in McHale's Bar in 1981, John offers Tommy a cigarette from a Marlboro cigarette box. However, when Tommy puts it into his mouth to light it, you can see a small camel on top of the cigarette.
Other mistake: At the end of the film, the narrated epilogue describes the fates of 4 of the principal characters. The narrator first says, "John Reilly's bloated body was found face-up in a tenement building" (suggesting that he was at least a few days into decomposition) following his death by tainted alcohol. This statement is accompanied by a black and white police photo of John Reilly's body; but the photo shows him quite trim and freshly dead, not bloated or discolored at all. The same mistake is made for the next character, Thomas Marcano (who was shot to death). The narrator says Marcano's body "lay undiscovered for more than a week." Once more, the statement is accompanied by a black and white police photo of Thomas Marcano's blood-stained body, which appears freshly deceased with no signs of decomposition whatsoever.
Answer: King Benny "sold" Henry's debt to Rizzo's brother, Little Caesar. He then informs Caesar that Henry was the one who killed his brother, knowing that he'd kill Henry, and that he could use the debt as an excuse.
Brian Katcher