Detective Michael Wuertz was a corrupted Gotham City police officer in The Dark Knight. He, along with Anna Ramirez, was corrupted and turned Harvey Dent into the Joker's man. He was a member of the Major Crimes Unit.
Before joining MCU, Wuertz had a history of corruption and was investigated by the then-Internal Affairs officer Harvey "Two-Face" Dent, who would later refer to him as "scum" and question Gordon's reasons for trusting him.
Wuertz's main focus at MCU is to identify the Batman, with which he has had no luck, with most suspects being utterly outlandish. Pictures of Abraham Lincoln, Elvis Presley, and the Sasquatch of the Patterson-Gimlin film were posted on his office wall. The task appears to be something of a joke, as Gordon's relationship with Batman is well known in MCU and, as Wuertz seems on his own, it may be proof that Gordon didn't trust him, giving him the case to distract him from mob investigations and to please those in the public against Batman.
Gordon later instructed Wuertz to find and protect Harvey Dent when the Joker named him as a target. Wuertz, on Maroni's orders, brought the Joker and his thugs into Harvey's fundraiser (under the guise of being forced to bring them at gunpoint).
Wuertz would further show his true colors when he sold Harvey Dent out to Sal Maroni. While driving him home, Wuertz kidnapped Harvey on Maroni's orders, though he claimed ignorance as to what would happen to Dent. Harvey would be dragged away from exploding gas cans by Batman, but his gas-soaked left side would ignite in the explosion, horribly disfiguring him. Harvey's girlfriend and would-be fiancee, Rachel Dawes, was killed in an identical explosion in another part of the city.
After the Joker claimed Gotham as his, Wuertz visited Lou's Bar, and when questioned by the bartender why he wasn't helping evacuate the city Wuertz claimed it was his day off. Harvey Dent, now horribly scarred on the left side of his face and going by "Two-Face," silenced the bartender on his way to the restroom, possibly by killing him. Two-Face appeared before Wuertz, and when he made the excuse that he didn't know what would happen to Rachel, Two-Face calmly stated "That's funny, because I don't know what's going to happen to you either." Two-Face then flipped a coin and it landed black, ending Wuertz's life with a handgun.
Commissioner Gordon would later note Michael Wuertz as one of those killed by Harvey Dent.
Behind the scenes
Michael Wuertz was portrayed by actor Ron Dean.