Joe Chill’s death isn't at Batman's hands, but a result of his own actions catching up to him, often referred to as "karmic justice".
💡 The episode is a "love letter" to Batman's history, featuring the voices of legendary Batman actors Kevin Conroy (Phantom Stranger), Mark Hamill (The Spectre), and 1960s stars Adam West and Julie Newmar as Batman's parents. [S2E11] Chill of the Night!
The episode highlights that Batman's moral code—not killing—is what prevents him from becoming as dark as the criminals he fights. Joe Chill’s death isn't at Batman's hands, but
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Batman discovers that a gangster named Lew Moxon hired Chill. To gain more insight, the Phantom Stranger takes Batman back in time to a charity ball where he briefly fights alongside his father, Thomas Wayne.
By solving the case and refusing to kill, Batman finally finds peace with his past, symbolizing this by closing his parents' case file.