The man accused of helping conceal the 2005 death of a south Georgia teacher Tara Grinstead has pleaded not guilty, the Ben Hill county clerk’s office said Monday.

Bo Dukes, accused of burning Grinstead's body, waived his arraignment and did not appear in court Monday. Last month, a grand jury indicted Dukes, who is charged with concealing a death, tampering with evidence, and hindering apprehension of a criminal in Grinstead's death.

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Investigators believe Dukes helped a former classmate, Ryan Alexander Duke, remove Grinstead’s body from her Ocilla home. Grinstead, 30, was last seen on Oct. 22, 2005, when she left a cookout and said she was going straight home. Two days later, she was reported missing when she didn’t show up at Irwin County High School, where she taught history.

In April, Duke was also indicted by a grand jury on six counts, including malice murder, felony murder, aggravated assault, burglary and concealing the death of another.

No arrests were made in the case until February, when a tipster contacted the GBI with information, The Atlanta Journal-Constitution previously reported. Duke was arrested first, followed by Dukes several days later.

The Ben Hill grand jury indicted Bo Dukes on three charges, accusing him of burning and hiding Tara Grinstead's body nearly 12 years ago.