POTOSI, Mo. (AP) — A Missouri prosecutor is seeking to vacate the conviction of a man who spent nearly two decades behind bars for the 1998 death of his mother — a crime he and others insist he did not commit.

Washington County Prosecuting Attorney Joshua Hedgecorth has asked a judge to set aside 38-year-old Michael Politte’s second-degree murder conviction, the Kansas City Star reported. Politte was released from prison last month, two months after he was granted parole.

Politte was just 14 when Rita Politte died in a fire at the family home in the eastern Missouri town of Hopewell. Michael and a friend were also in the home but managed to escape the blaze. Politte’s lawyers said the boys were awakened by smoke and scrambled to escape, before Politte found the burning body of his mother.

Investigators said the fire was started with gasoline and determined that Rita Politte had also suffered blunt force head trauma. The investigation focused on her teenage son as the main suspect, and four years later he was convicted as an adult and sentenced to life in prison.

The only physical evidence investigators had to link Michael Politte to the crime was what they said was the presence of gasoline on the teen’s shoes. But that finding was based on now-discredited fire investigation techniques, and the state has conceded there was no gasoline on his shoes.

His attorneys have said investigators ignored other potential suspects, including Politte’s father, who was going through a difficult divorce with Rita Politte when she was killed.

The Midwest Innocence Project and the MacArthur Justice Center, which both work to overturn wrongful convictions, have sought to exonerate Politte.

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