A Georgia man was sentenced to 25 years in prison Friday for helping burn the body of a slain teacher whose grim end in a rural pecan orchard remained a mystery for more than a decade.

A judge in Wilcox County ordered the maximum possible punishment for 34-year-old Bo Dukes the day after a jury convicted him of concealing the 2005 death of Tara Grinstead. Before the sentence was read, Dukes offered a tearful apology to Grinstead's family.

"I'm truly sorry. Your long suffering has been unimaginable," Dukes said in court, turning from the judge to address the dead woman's family. "My actions were cowardly, callous, and cruel. I was more interested in self-pity and self-preservation than doing the right thing for Tara and for you."

A high school teacher and former beauty queen, Grinstead was 30 when she vanished from her home in nearby Ocilla in October 2005.

A billboard bearing her photo and the phone number of a tip line loomed for years in the area as Grinstead's family held out hope she might be found alive. No answers came until February 2017 when authorities arrested Dukes and a friend accused of being Grinstead's killer.

"For over 11 years, he watched all of us who loved her suffer unimaginable pain and heartache as we frantically searched for her," Connie Grinstead, the slain woman's stepmother, told the judge Friday.

She asked for Dukes to receive the maximum penalty, saying: "He did nothing. He just went on living his life."

Superior Court Judge Robert Chasteen Jr. granted that request as he sentenced Dukes to 25 years imprisonment for concealing a death, hindering the apprehension of a criminal and two counts of lying to police.

Defense attorney John Fox asked for a 12-year sentence for Dukes, news outlets reported. The charges all stemmed from a June 2016 interview with a Georgia Bureau of Investigation agent in which Dukes denied having told an Army buddy a decade earlier that he helped dispose of Grinstead's body.

Dukes confessed a few months later in February 2017. He told the GBI his best friend had broken into Grinstead's home and strangled her in bed, then used Dukes' truck to take the body to a pecan orchard owned by Dukes' uncle. Dukes said he helped his friend move Grinstead's body deeper into the woods, where they spent two days burning it until only ash and small bone fragments remained.

Dukes' friend with a similar last name, Ryan Duke, is scheduled to stand trial April 1 for Grinstead's murder in nearby Irwin County, where she lived. Authorities say Duke also confessed, saying he broke into Grinstead's home to steal money for drugs, and they found DNA from both Duke and the slain woman on a latex glove found in her yard.

Duke's defense attorneys have said he gave a false confession under the influence of drugs. The say in court filings that Duke was home asleep when Grinstead was killed.

Though Dukes has been sentenced as an accomplice, his legal troubles aren't over. He still faces charges in Ben Hill County, where Grinstead's body was burned. And earlier this year, police charged Dukes with sexually assaulting two women at gunpoint on New Year's Day while he was free on bond.