Looking back, it's a little surprising that the creators of Batman waited until 1948 to dive into the details of Joe Chill's origin, but to be honest, they were always a little slow on that score. They didn't give him an origin story at all until six months after his first appearance, in Detective Comics #33, and while that introduced Crime Alley and the trigger-happy mugger, it would be another eight years before he even had a name.

In Batman #47, Bill Finger and Bob Kane finally did the job with "The Origin of Batman." A chance encounter with a crooked trucking company specializing in transporting criminals across state lines led Batman to the company's owner, Joe Chill—and when he saw his face, the Caped Crusader immediately recognized the man who shot his parents all those years ago, and swore to bring him down once and for all. Rather than just clocking him in the jaw and dragging him off to jail, though, Batman confronted Chill personally, unmasking and explaining why he was about to exist entirely within a world made of batarangs and pain.

With the only other option being to stand there and lose his teeth four or five at a time, Chill ran into another room and explained his problem to a trio of henchmen. Unfortunately, he also had to explain that he was personally responsible for creating the single greatest scourge the criminal underworld had ever known, and his fellow crooks were pissed to the point of gunning him down before he could reveal Batman's identity. With that, Joe Chill was introduced and killed off in the span of a single 13-page story, closing the case on the Wayne murders forever.