Somehow, talking about the World Cup led us to talking about baseball, which somehow led us to talking about Andrew Cunanan, which led to a discussion about the greatest serial killers of all-time. Okay, so we should probably use “prolific” over greatest, but you get what we mean (we hope). We will warn you, however, that we are not experts on serial killers so there will be notable admissions. We apologize in advance to HH Holmes.