(ONN) – In Cleveland, 11 people have been charged in a plot to smuggle synthetic drugs into federal prisons by soaking papers in drugs.

The U.S. Attorney’s Office in Cleveland says drug-infused papers were snuck into prison mail disguised as fake legal documents and Harry Potter coloring books.

The charges allege prisoners receiving the mail sold the papers to other inmates for $500 a page through a Bureau of Prisons payment system or other means.

The pages would then be cut into strips and smoked.

Prosecutors say the smuggling happened between 2015 through last year.

The prisons weren’t identified.