An Atlanta jailor intercepts a Murder Plot Letter

At Fulton County Jail in Atlanta, Georgia, guards are under the constant threat of violence — both inside the jail and outside.

Inmates have been known to coordinate crimes with people outside the jail through a variety of methods, including illegally obtained cell phones and written correspondences containing elaborate codes.

Last year, that practice was taken to the extreme, and nearly resulted in deadly consequences.

Chief jailer Col. Mark Adger told Business Insider that in September 2017, the jail intercepted a letter from an inmate that looked innocuous at first glance, but was actually encrypted with secret instructions for the recipient to murder a staff member at the jail.

The incident took place after the filming of “60 Days In,” an A&E documentary series that takes place at the jail. Adger provided Business Insider with a copy of the original letter.

“If you read the letter and didn’t know it was encrypted, you would think it was a standard, regular, ‘how you doin,’ ‘my day is fine’ kind of letter,” Adger told Business Insider.

The inmate who sent the letter, whose name has been redacted, was in Fulton County Jail on charges that included murder, armed robbery, and aggravated assault with a deadly weapon. Because of the inmate’s known affiliations to an organized gang — 20% of the jail’s roughly 2,500 inmates are in gangs — Adger thought the letter deserved a closer look.

He sent the letter to a cryptanalysis expert at what he called “a three-letter organization,” and got back the decoded message within the hour. The seemingly innocent letter was actually an orchestrated hit on one of his employees.

“Put a team together and cease this rat,” the translated letter read, before listing the name of a jail employee, two of her family members, and their addresses, according to documents provided by Adger. “My loyalty is to you and the family. Press the gass [sic] on this.”

The decoded message left Adger stunned.

“When I got the decryption back, and I compared it to the plain text correspondence, I said, ‘How in the hell did they get this from this?'” Adger told Business Insider.