A Tennessee man who was a key witness in the Holly Bobo murder case has been found dead in an apparent suicide -- and in a perverse twist, he went to elementary school with her cousin, country singer Whitney Duncan.

Bobo, a 20-year-old nursing student from Darden, Tenn., went missing in April of 2011. Her remains were discovered more than three years later, on Sept. 7, 2014, in a wooded area of Decatur County, Tenn. Zachary Adams has been charged with aggravated kidnapping and first-degree murder in Bobo's death.

30-year-old Shayne Austin was given an immunity deal in March of 2014, just a week after Adams' indictment was announced. Austin was offered immunity in exchange for his testimony in the case, but the district attorney later rescinded that agreement, claiming that Austin had nullified the deal by not being truthful and fully cooperative.

Austin took civil action against the state, which was still pending when he was found dead. Nashville's WSMV reported Monday (Feb. 23) that according to his attorney, Luke Evans, Austin committed suicide out of state.

"Obviously a tragic loss for the Austin family and they are besides themselves with grief," Evans says.

Austin was still considered a person of interest in the murder, but had never been charged.

"It's unfortunate the government came in and made allegations without basis. People had to live with those allegations ... under the cloud of those allegations," Evans adds. "Mr. Austin's position was that he was immune not just from being convicted of a crime, but charged with a crime ... He's maintained this from the beginning that he had nothing to do with the tragic circumstances that befell Ms. Bobo."

Duncan reacted to the news of Austin's death on Facebook:

Zach Adams' younger brother, Dylan, is charged with evidence tampering in the Bobo case. Jason Wayne Autry has been indicted on charges of aggravated kidnapping and first-degree murder, while brothers Jeffrey and Mark Pearcy are charged with tampering with evidence and accessory after the fact.