UPDATE: Achterberg pleads guilty to amended second-degree murder charges in Boone County

A Columbia man with a lengthy criminal record was sentenced to 20 years in prison for the 2021 shooting death of Justin Stidham north of Columbia.

939 The Eagle News was at the Boone County Courthouse Friday afternoon for the emotional preliminary hearing for 39-year-old Mark Achterberg, who was scheduled to stand trial Monday on charges of first-degree murder and three other felonies. Boone County Prosecutor Roger Johnson changed the charge and Achterberg pleaded guilty Friday to second-degree murder and unlawful possession of a firearm.

Achterberg, handcuffed and shackled and sitting next to defense attorney Kevin O'Brien, tells Boone County District Judge Jeff Harris that he shot Stidham in 2021. Achterberg did not tell Judge Harris why he killed Stidham.

Boone County Prosecutor Roger Johnson then called two Stidham family members to testify: Wayne Stidham, Justin's father, and Susie Pemberton, Justin's sister. Wayne Stidham looked directly at Achterberg in the courtroom and told him that today was not his judgment day, adding: “I hope you spend your eternity in hell.” Mr. Stidham told Achterberg that Justin would never let his children grow up will see, saying that the suspect “took that from us.” Mr. Stidham also warned Achterberg about his future in Missouri prison, describing Achterberg as a coward. “Cowards don’t do well in prison,” the father told him as at least six bailiffs and Boone County sheriff’s deputies watched nearby.

Mrs. Pemberton, the sister, tells Judge Harris that the murder had a major impact on the Stidham family. “We will never feel his hugs again.” Pemberton tells Judge Harris this wasn't easy. Judge Harris leaned forward in his chair and listened intently to the testimony.

Achterberg was arrested by authorities in the Hawkeye State after the murder in 2011. He has been in prison since November 2021 and will receive credit for the nearly three years he served in prison.