The police finding Napier at the chemicals plant was the doing of mob boss Carl Grissom (Jack Palance), who set him up in revenge for sleeping with his mistress. However, after Napier is transformed into The Joker, he heads to Grissom's penthouse, revealing his new, colourful appearance, before gleefully filling Grissom with bullets, wildly firing as some carnival-style music plays out. If nothing else, The Joker's introduction here makes it clear exactly what Burton and Nicholson's interpretation of the character is: creepy, cartoonish and pretty damn goofy as well.