Why was there a concentration of serial killers in California during the 60’s/70’s?

Question

What caused this to happen?

Why were most of the documented 20th century serial killers American?

What behavioral “type”/“profile” leads to serial versus mass versus spree killer?

In: Other

Answer 1

Because the KKK killing multiple black people weren’t considered serial killers? Although this would more so apply to early 1900s USA then 1960s. But the KKK were active then.