- "My mother was a cold-hearted whore who never loved anyone."
- —Jerome about his mother, Lila.[src]
At some point in time, Lila had a relationship with Paul Cicero, who she conceived Jerome with. According to Jerome when the circus traveled to Kansas City at the time of his 9th birthday, his mother along with a man both boozed, boned, and beat him up. When he was crying outside the trailer, Cicero told him that the world didn't care about him and that it was better to realize it then.
When the circus came to Gotham City, Jerome murdered her with a hatchet in Cicero's trailer. He then cleaned up the blood and threw the murder weapon off Arkham Bridge. The body was discovered and hidden by the circus performers, who intended to find the killer themselves and carry out vigilante justice, but this was prevented when Detective Jim Gordon found the body and investigated the case.
Gordon eventually deduced that Jerome was responsible and that Cicero is his father. In the interrogation room Jerome broke down into maniacal laughter, and referred to his mother as a drunken whore and that he killed her because she kept nagging him.
- "Rise of the Villains: Damned If You Do..." (mentioned)
- "Rise of the Villains: The Last Laugh" (mentioned)