Fred and Rosemarie West
This couple terrorized England in the 60’s and 70’s, by killing numerous girls and young women, including their daughter.
The initially started with sexual abuse of their daughter’s babysitter, and escalated to full on murder and body disposal in their basement.
After one of the abuse victims came forward, their whole life unravelled and they were arrested. Both were put on trial, but Fred ended up committing suicide before his conviction in 1995, while Rosemary’s probably gonna die in prison.
You forgot Harold Shipman, probably the world's most prolific serial killer and a doctor.