There are two of me in each normal human brain, and we are both shaped like an almond, after which we are named.

FORBES: I Am America's Amygdala

Psychologists and criminologists would later speculate that West was a sociopath - unable to feel normal human feelings or empathise with his victims, possibly due to a brain injury he had suffered in a motorbike accident.

BBC: The chilling voice of Fred West