The Gotham City Police Department is the local city law enforcement agency for Gotham City.
Acting as both ally and opponent of Batman, the Gotham City Police Department has long been steeped in political corruption dating through the majority of the twentieth century, with numerous officers both high-and-low ranking involved in bribery and even more serious offenses such as drug-trafficking and murder.
The corruption stemed from the mayor's office and continued throughout the law enforcement and judicial branches of the city government.
During the events surrounding Batman's rise as Gotham's defending hero, Police Commissioner Gillian B. Loeb was under the bankroll of Carmine Falcone, mafia boss of the Falcone family, who made sure Loeb and his forces did not interfere with his operations.
Willfully working with Falcone, Loeb was targeted by Batman amongst other underworld figures. Ordering a massive police taskforce to capture the Batman at all costs an increasing amount of conspiracy charges, brought forward by District Attorney Harvey Dent, against Loeb forced him to resign his position, he was replaced by equally corrupt Commissioner Peter Grogan.
After the death of Carmine Falcone, the mafia lashed out in retaliatory crimes which severely crippled organized crime in Gotham City. As a result the waning presence of corrupt police officers on the force allowed Lieutenant James Gordon, a man determined to fight corruption in the GCPD, to become the new police commissioner.
Gordon served as commissioner for a long period despite continued mayoral interference, assisted by the Batman in bringing justice to Gotham until a near fatal gunshot from a corrupt cop forced his retirement.
His successor, Commissioner Michael Akins took a less lenient approach with Gotham's vigilante heroes and ordered the shoot-to-kill order of Batman and the estrangement of the police force from the hero's activities. Corruption within the police department rose once again during Akins' tenure as Commissioner before he was replaced by Gordon's return to the post of Commissioner nine months after the Infinite Crisis incident and relations with the Batman were re-established three months after that.
While Gordon had developed a strong respect for Batman and his efforts, the rest of the police cast a suspicious eye in his direction. When the Bat-signal was first used to summon the Batman, the Gotham populace thought it was a scare tactic directed toward the city's criminal element.
The division that handles murders and some of the more serious non-metahuman crimes in Gotham. This is the division Gordon was a part of before becoming commissioner. Harvey Bullock formerly worked in this division. Former private investigator Jason Bard is now working on homicide cases for this division.
Major Crimes Unit
Developed in response to the continued battle between Gotham's Crime Families and the rising tide of costumed criminals, the Gotham MCU was previously operated by Harvey Bullock and deals with the most serious crimes, often involving supervillains or politically sensitive cases. Following Bullock's retirement, the MCU is now led by Captain Maggie Sawyer, previously an officer in the Metropolis Police Department's MCU.
Quick Response Team
Led by Lt. Gerard "Jerry" Hennelly, the Quick Response Team is the GCPD's SWAT unit. The most rigorously-trained of all GCPD squads, the QRT is a rapid-deployment unit drilled in anti-terrorism maneuvers to combat Gotham's unique criminal element.
Following the Infinite Crisis, the GCPD created a sub-division to deal exclusively with Metahumans. Possessing equipment provided by S.T.A.R. Labs, this squad is deployed for specific metahuman situations.
During Gotham's No Man's Land, many Officers of the GCPD remained in the city to help maintain order. When the city began seperating into factions, the GCPD became known as the Blue Boys, led by ex-commissioner James Gordon.
Batman provided what would be known as the bat-signal to newly promoted Police Commissioner Gordon as a symbol of trust and a way they could communicate with each other without skulduggery.
To protect the Gotham City Police Department from the political remnifications of summoning a costumed vigilante, no representative of the police was allowed to access the bat-signal. Instead the G.C.P.D. employs a civilian aide to handle the light.