DECATURVILLE, Tenn. - Attorneys for two men charged with kidnapping and murdering Tennessee nursing student Holly Bobo are asking for those charges to be dismissed, citing lack of evidence.

CBS affiliate WTVF-TV reports the motion by the attorneys for Zach Adams and Jason Autry states that they have yet to receive "dental records analysis and forensic studies" of a skull that law enforcement says is Bobo's.

"It would appear to me if they had a skull with a dental match they would have given that to us right away. It's a little suspicious why we don't have that forensic information," Autry's attorney Fletcher Long told the station.

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The 20-year-old Bobo was last seen April 13, 2011, when she went missing from her Decatur County home. Her remains weren't found until September 2014, just months after the first arrests were made in the case.

Adams has been in jail since March and Autry has been in jail since April. At a court hearing on December 17, Decatur County Circuit Judge Creed McGinley expressed concern that prosecutors had not yet provided key evidence to defense attorneys. He ordered the state to begin turning it over by December 24.

Long says the state has missed that deadline.

He says he has received nothing linking the suspects to a homicide.

"It would seem to me in a murder case the first thing they would want to give us is proof that someone has been killed," Long said.

The motion filed by the attorneys accuses the state of "silence or stonewalling." It asks that the charges be dismissed. Short of that, it asks the judge to sanction the state and order it to pay the defense team's fees for being forced to file and argue the motion.

McGinley, the judge, said at the December hearing that he had been patient with the prosecution because a new district attorney general, Matt Stowe, had just been elected in September. However, McGinley warned that he would not stand for more delays in the case.

But later that same day, Tennessee Bureau of Investigation Director Mark Gwyn announced that he was suspending all work on the Bobo case after Stowe accused TBI agents of misconduct. The dispute was only resolved after Stowe agreed to request a special prosecutor be appointed.