The Axeman sent a letter to the Times-Picayune in March 1919 declaring that any household playing jazz music at 12:15 a.m. on the following Tuesday would be spared. The city complied en masse. No attack occurred that night. But an even more specific behavioral pattern connected all the actual attacks throughout the series: something the killer always did — or conspicuously never did — that no Mafia extortionist would logically bother with. What was it?