The socioeconomic status most likely to create a serial killer is most commonly found amongst white males. The type of upbringing held by similarly disturbed people in other classes push them towards other forms of antisocial/criminal behavior. Further, the theoretical genetic predispositions that incline a person to the personality disorders associated with serial killers are found more often amongst Caucasians.
There are more white people in North America, so the probability is higher. Keep in mind that people of various ethnicity, English, Irish, French, etc... are considered "white. "
Serial killers have a very specific profile. They're often raised a certain way and are exposed to certain elements that make them that way, and whites tend to have that.
