Leslie DeSantis is a madam who employs young male prostitutes for older women.
After one of her prostitutes Tommy Dowd is assaulted by Gary and Darlene Sutton, Detectives Elliot Stabler and Olivia Benson question DeSantis about her business. She lies and says that her prostitutes aren't allowed to have sex with their clients. After James Coe is attacked, the detectives question her again and she tells them that she fired Coe for stealing money from her. Dowd later reveals that he once took a loan from DeSantis and she in turn made him have sex with her. However, when she started to get to possessive, he tried to break it off but she threatened to withdraw the loan if he did so. When the detectives start to suspect that DeSantis is knowingly sending prostitutes she has problems with to the assailants, they have Dowd go to her apartment to speak to her with a wire.
While they were talking about what happened to the other prostitutes, DeSantis says that Coe got what he deserved and eventually discovers the wire. She then calls Dowd ungrateful and almost kills him by throwing boiling stew on him, which gives him extremely severe burn wounds. While Benson tends to Dowd's wounds, Stabler arrests DeSantis and tells her that if Dowd dies, she will get the death penalty. While being arrested, DeSantis spits on Dowd. While at Rikers, A.D.A. Alexandra Cabot tells DeSantis and her attorney that she needs to reveal the couple who have been assaulting her escorts in order to get a good deal, but DeSantis reveals that the couple always paid using a different credit card and that she didn't know it was the same couple. She is currently imprisoned for promoting prostitution and for attempting to murder Dowd.