Jennifer San Marcos literally lost her mind, when she went to the postal branch she was formerly employed at, becoming responsible for eight deaths!  

References:

https://youtu.be/qzd-4PVVn2U?si=aMeWEv9rq3xXDq0u

https://youtu.be/qzd-4PVVn2U?si=QideH9DOyvB1_oCN

Brantingham, Barney. (January 31, 2013). “The Goleta Postal Murders”. Santa Barbara Independent. https://www.independent.com/2013/01/31/goleta-postal-murders/

Sutton, J. (May 11, 2021). “A Woman Scorned”. Criminal Behaviours. https://www.criminalbehaviours.com/post/a-woman-scorned