These cops were killers. Welcome to WatchMojo, and today were examining the most notorious serial killers from around the world who worked in law enforcement in one capacity or another before or during their horrific crimes. Our countdown of cops who turned out to be serial killers includes Anthony Sully, Dennis Nilsen, Joseph James DeAngelo, and more! Which of these stories did you find the most shocking? Let us know in the comments.

Watch more serial killer videos here:
10 Serial Killers That Are STILL ACTIVE: https://youtu.be/HEKmC0y4nqk
20 Cold Cases That Were Finally Solved: https://youtu.be/aFlo8G7NpsM
Top 20 Serial Killers Who Were Never Caught: https://youtu.be/S8eo4-URLpA

Become a channel member to get access to special perks:
https://www.youtube.com/channel/UCaWd5_7JhbQBe4dknZhsHJg/join

Dont forget to play our Live Trivia games at 3pm EST for a chance to win cash! The faster you answer, the more points you get!: https://www.watchmojo.com/play

Have your idea become a video!
https://wmojo.com/suggest

Subscribe for more great content!
https://wmojo.com/watchmojo-subscribe

Visit our shop for awesome merch!
https://shop.watchmojo.com/

Your trusted authority for Top 10 lists, reviews, tips and tricks, biographies, origins, and entertainment news

#Cops
#Crime
#SerialKillers
#Killers
#Criminals
#Police
#Arrested