„After the critical success of the film (King of New York), Ferrara was expected to follow it up with a big-budget re-run of similar themes, or to take on a fat pay cheque directing job. Instead, he shot his tour de force, independent film masterpiece, Bad Lieutenant in a mere 20 days on a minuscule budget that Kent Jones claims in the „Hard Press" to have been approximately $1,000,000. An initial cheque for $40,000 from Hollywood producer Edward R. Pressman got the film off the ground, as Ferrara explained to Sight and Sound: „I don´t know what possessed him to give me that money... Nicky St. John didn´t want to write it for reasons of his own. So Zoe Lund, star of Ms.45 came in, we worked together. She wrote it very quickly, at least the first draft and we needed a draft in two weeks." Ferrara told Empire in typically dry fashion how the writing collaboration worked out: „I´d tell her a bunch of shit and she´d make sense of it." 
Ferrara had already conceived the idea for the film from two sources. The first was a Bob Dylan-inspired folk-blues song which he had written called „The Bad Lieutenant". The second, which gave the song its subject matter, was a news story that dated back to 1982 about a nun who was raped in Spanish Harlem. Although Ferrara had been as shocked as any other New Yorker by the story, he also wondered why the rape of a nun was elevated to priority police and media status when hundreds of other rapes passed by every week with barely a mention. He combined the story and his reaction to it with another  idea about a police lieutenant with every vice known to mankind. Ferrara turned this recipe of ideas into the song „Bad Lieutenant"
(which plays out the alternate cut of the film after Schoolly D´s track „Signifying Rapper" had to be replaced due to legal problems) which, in Ferrara´s words, was about a lieutenant with „a wife and five kids and a house by the park" who has a mistress, a drug habit, is completely corrupt and is investigating the rape of a nun. He would later give Film Ireland a different theory on where the Lieutenant´s character sprang from: „The Bad Lieutenant emerged from my imagination and I´m stuck with him. You know people who have all these different vices and you think, „Man, what if you had one guy who had every one of ´em, and then if he was a cop on top of that, so he has a gun and a badge to go with his womanising and alcoholism and everything else?" I thought that´d make a pretty funny movie. Then we hired Harvey Keitel and out went the humour." 
 

The end of the Bad Lieutenand-analysis (p.143-144)

„It is an acutely moral film, from the title, which tells the viewer straight from the word go that the main character is thoroughly reprehensible, to the nun´s act of forgiveness and the religious imagery that constantly stalks the Lieutenant like his conscience unravelling. Shot in real time, the film gives the viewer no excape, no breaks in the narrative to provide light relief. Apart from the nun´s rape and the interludes with Zoe and the nun, the Lieutenant is constantly in our faces, rubbing our noses in his degradation... 
„the films´s use of space, sound, editing and pacing is as unusal as  the definition of its central character." The Lieutenant´s personality is reflected back in the way in which Ferrara presents the film..."

„Bad Lieutenant closes with a beautiful, moral ending, loaded with issues of redemption and forgiveness, as the Lieutenant sacrifices himself to free other sinners. The nun points out to him that Jesus died for his sins just before he sees Christ. The Lieutenant dies for the rapists´ sins, his sins washing theirs clean. It is this moral leap that he struggled with, and it is this same issue that we as viewers struggle with after the film has finished. The Lieutenant constantly asks himself (and the nun and rapists) how the nun could forgive such an act. When the film ends, we also ask ourselves how 
he could forgive the rapists and sacrifice himself to save them. The film is an essay on the complexities of Christian faith."