Only one of the five women was a prostitute. They were all destitute and had no where to live, they didn't have any means of making money. The evidence doesn't support that he was having sex with them or some interaction was happening which would make sense if they were prostitutes. Most of these women were alcoholic and they were killed on the streets when they were drunk basically. Suggesting that the murderer just preyed upon these women who were completely vulnerable and weren't even able to scream out for help.