If people suspect you of being a serial killer, you're probably not a great serial killer.
The scary fact is that there are a lot of people out there that appear completely normal, like business men, hedge fund managers, etc that would be your last guess to be a serial killer. But they are, and they rack up insane numbers because they are smart and no suspicion ever lands on them.
The guys you hear about that get 10- 15 hookers and then get caught are the sloppy less impressive serial killers. I would be willing to bet there are at least 5 guys in the US that have over 20 bodies each and have never so much as been questioned by law enforcement. They are that good.