Jerome Valeska and the other members of the Maniax entered the building after Barbara Kean lured Jim Gordon outside and down an alleyway, where Aaron Helzinger beat him into unconsciousness. Jerome began the massacre by holding Commissioner Sarah Essen at gunpoint; the other thugs then killed nearly all the cops inside the building with shotguns.
After the cops were incapacitated, the Maniax finished the wounded ones and Jerome and Robert Greenwood made a video of Jerome menacing Sarah, with Jerome telling Sarah that the Maniax would leave a mark on the city. Greenwood said a line that Jerome considered to be his - that 'there's nothing more contagious than laughter' - and in return Jerome shot him dead. Jerome then killed Sarah and finished the video before fleeing the scene.
It was revealed that Andrew Dove had taken part in fighting the Maniax during this event before becoming an informant to Dwight Pollard. This was mentioned when Gordon and Harvey Bullock were trying to get answers out of Andrew Dove on what Dwight was planning.
- † Sarah Essen
- Jim Gordon (injured)
- Leslie Thompkins
- Edward Nygma (injured)
- Kristin Kringle
- Andrew Dove
- † 9 GCPD members
- "Mad City: Smile Like You Mean It" (mentioned)