It's common lore of Star Wars, but they mentioned it in the Star Wars: The Clone Wars animated series and it was carried out in Episode III: Revenge of the Sith when the Emperor commands all of the clone troopers to kill the Jedi (All of them).
It is also known as "The Great Jedi Purge".
But how is Dark Lord Spaniard Genova able to Order this purge?
Does he have Clone Troopers at his disposal?
Or by Clone Troopers does he mean Lenny and the other misfits? (Odor 66 instead of Order 66 since they smell?)
Why is he going after Kai Muscle?