The mystery drives Bruce so crazy, he steals Barry's Cosmic Treadmill and goes to the past. Becoming more and more agitated, Bruce finally comes across little him and his parents, but no gunmen. At the end of his patience, Bruce jumps out and demands to know where the shooter is. His parents jump back, blocking his child's form's vision from a clear view. Screaming in rage, Bruce yanks his mother closer to him by the necklace, but her purse accidentally sets off Bruce's grapple gun. Going through her chest and into his father's.
And so, it is revealed that Batman created Batman! Time paradox you say? I have the perfect counter; because Batman!