I don’t believe all of those were from Detroit.
He does link his source
Yes, not just Detroit.
These are white bigots. I have little trust in their muck-raking. My other comments still stand, although undoubtedly some actually count as real mass and serial. They just didn’t get very far.
No question the Beltway Snipers counted, although their MO was very odd for serial killers. Serials usually do everything in secret. Total.