This episode covers one of the most prolific (jury is still out on the use of this word to describe someone who kills people) serial killers of all time that you've never heard about  

Grab some coffee, plant your kill and sewing kits, and let's get vile 

Sources: 

https://thebrag.com/israel-keyes-serial-killer/

https://www.biography.com/crime-figure/israel-keyes 

Reddit

Wikipedia