The investigation into the killing of Holly Bobo has not been smooth. The suicide of Shayne Austin is the latest twist.  Bobo, a 20-year-old nursing student, disappeared in April 2011. Her remains were not found until last September, in Decatur County.  Shayne Austin was never indicted, but was in prosecutors' sights and was threatened with possible charges.  Two other men -- Jason Wayne Autry and Zachary Adams -- are charged with especially aggravated kidnapping and first-degree murder in Bobo's killing. Both have pleaded not guilty.  Bobo family: Killers 'lost their souls' 02:34  Austin's role in the case, according to attorney Luke Evans, was to cooperate with authorities in exchange for immunity from prosecution.  Days after Austin was granted immunity in March 2014, the state tried to void the deal and tried at least twice to indict Austin, his attorney said.  As a result, Evans filed a civil breach of contract suit against the state, asking the court to enforce the immunity deal as well as a restraining order to prevent the state from further attempts at indictment. That case is pending in circuit court, Evans said.  The state said it revoked the immunity agreement because Austin was not being truthful or fully cooperative, CNN affiliate WSMV reported.  Evans told the affiliate that his client always maintained that he had nothing to do with Bobo's death.  Bobo's brother told authorities he saw a man in camouflage leading Bobo away from their home in Darden in April 2011.  Volunteers from at least five counties searched for the student, and donors raised more than $450,000 in reward money to help find whoever was responsible.  Investigators ruled out early reports that Bobo had been dragged away from her home, but they didn't believe she left of her own free will, either.  "We feel she was in fear of her life so she was compliant with his demands," a Tennessee Bureau of Investigations (TBI) special agent said at the time.  Missing Holly Bobo's remains found 01:02  Bobo was on her way to school when she disappeared.  Suspects Autry and Adams were indicted in March 2014. Information from "several witnesses" led to charges against them, the head of the TBI said then.  Investigators "believe there are more people with information and possible involvement," the TBI said.  Months later, in December, the TBI announced that it was withdrawing from the investigation. In a statement, the agency said that the district attorney accused the TBI of misconduct, along with other law enforcement agencies. At the district attorney's request, the TBI stopped its investigation.  But shortly afterward, the TBI resumed its work on the Bobo case after the district attorney took himself off the case and appointed a special prosecutor to handle it, according to The Jackson Sun.  CNN's Holly Yan contributed to this report.
A man who Tennessee authorities tried to indict in connection with the kidnapping and killing of a nursing student has committed suicide, his attorney said.