Loeb was also a character in the Batman comics who ran the Gotham police early on in Batman's career. Unlike his movie counterpart, the comic version of Loeb was utterly corrupt and supported the operations of the Falcone mob in exchange for hefty bribes.
In The Dark Knight, Commissioner Loeb's life is threatened by The Joker. Jim Gordon informs Loeb of the threat after his DNA is found on a playing card tucked away in a file on the various Gotham mob heads, the Joker's way of telling the police who he's targetting. Loeb is unconvinced that the threat is genuine and pours himself a scotch. However, the whiskey is tainted with some kind of acid, as evidenced by vapours pouring out of the glass after Loeb drinks from it. Loeb is poisoned by the tainted whiskey and dies within seconds.