Tennessee sheriff's office inadvertently put out wrong info on Delphi double killings

— -- The Indiana State Police says a sheriff's office in Tennessee inadvertently released incorrect information on the mysterious killings of Delphi, Indiana, eighth-graders Abby Williams and Libby German.

According to the state police, the Bledsoe County Sheriff Department wrote on Facebook that “FBI has extended the search" for Abby and Libby's killer or killers into southeastern Tennessee counties, including Bledsoe.

Authorities initially published a grainy image of who they say is the prime suspect in the investigation and broadcast a chilling recording found on Libby's phone with just three audible words: "Down the hill."

Police later released a composite sketch of a man believed to be connected to the killings.

The state police in a news release said the post by the sheriff's office was incorrect, stressing, "In fact, this is a NATION WIDE search for the person or persons wanted for the murders of Abby and Libby."

The sheriff's department wrote in a new Facebook post, "To Clarify this suspect HAS NOT BEEN SEEN IN BLEDSOE COUNTY or any other counties in Tn. It is a nationwide search."

Bledsoe County Sheriff Jimmy Morris told ABC News the initial Facebook post was "just a misunderstanding."

Over 11 months ago, on Feb. 13, Abby, 13, and Libby, 14, who became good friends as volleyball teammates, were enjoying a day off from school when they disappeared on a hiking trail near their rural hometown of Delphi.

Their bodies were found the next day.

In the nearly a year since their deaths, no arrests have been made.

As the months have ticked by, clues in the mysterious double killing have been few and far between.

The Indiana State Police today said the investigation is ongoing with over 26,000 tips investigated.

"We are confident someone knows who was responsible for these murders and we encourage them to come forward with their tip information," the state police said in a news release.

Anonymous tipsters can call 844-459-5786 or email abbyandlibbytip@cacoshrf.com.