Doesn’t seem like it would take a very big jail to hold 50 people.
Catch them, kill them, cook them and eat them.
Just as an example to anybody else who would attempt such a way of life.
It is not the size of the jail, it is the size of the legal corps who are dedicated to keeping as many miscreants out of jail as they can argue before sometimes very compliant and/or lenient judges.
Prosecution fails, not the law enforcement aspect.
250 feet by 8 feet of good easily digable earth could solve the same problem.