Continuity mistake: When Bateman goes crazy and flees into his office, his hair is very messed up. However just after he sings and goes to his office, it is quite obvious his hair has been redone and gelled again.
Visible crew/equipment: In the scene where Patrick Bateman is walking the streets, just before that encounter with the lady who is waiting for the red light to change, you can see the camera crew reflected on the store windows.
Continuity mistake: In the scene where Patrick is in his office working on a crossword puzzle before talking to Jean, he is writing with his right hand. When the shot changes to the reflection of Patrick's glasses, the reflection shown is as if he is using his left hand. The reflection isn't a mirror image as it should be.
Character mistake: Patrick, being the music buff that he is, mistakenly claims that Huey Lewis' Fore! came out in 1987, when it was actually released in 1986.
Answer: The situation is intentionally left vague. The homeless man being murdered wouldn't necessarily make the news in the time (there were over 4000 murders in 1989-90 when the book and movie are set). He and his friends are so alike that they continually mistake each other for others. The prostitutes would likely be loathe to call the police because they might be arrested themselves and he would likely get off with a much better lawyer.
Greg Dwyer