Two brothers who shot and killed a sheriff's deputy have placed photos of the slain lawman outside the entrance of their farm, calling it a "warning" to other law enforcement officials.

The Associated Press reports that the photos show the "bullet-riddled bodies" of Roane County Deputy Bill Jones and ride-along Mike Brown, who were shot and killed on May 11, 2006, after arriving at the home of Rocky Houston to deliver an arrest warrant.

"It goes without saying that any public display on their own property of these photos in whatever manner by the Houstons is despicable and certainly runs counter to the Houstons' claims of innocence," District Attorney General Russell Johnson said in a news release.

However, it also appears that the sign is perfectly within the Houstons' First Amendment rights.

"We are trying to report federal crimes, and we feel like our plea has fallen on deaf ears," Rocky Houston told AP.

Rocky and Leon Houston were acquitted of murder charges when prosecutors were unable to prove that they fired first after Jones and Brown entered their property. The Houston brothers insist that the two men showed up to kill them and opened fire without warning.

Both brothers were acquitted in separate trials in 2009 and 2010. However, Brown's family was awarded $5 million in damages in a wrongful death suit against the Houstons, which was settled in April 2012.

Chief Deputy Tim Phillips, who was friends with Jones, says the posted images are painful to view. "To see anybody, let alone someone that you knew, someone who wears the same uniform and does the same job as you, it's really disturbing to see that whether it's on a billboard or whether it's on the Internet. It's awful," Phillips told local TV outlet WATE.

The Houston brothers obtained copies of the crime scene photos during their trial and have posted them, along with various legal documents, on at least six different locations on their property.

A local resident briefly posted the photos to Facebook, but they were removed after a request from Johnson.