A postconviction relief request from a Lake City man convicted for a 2014 double homicide in Glidden is scheduled to go to trial later this month in Carroll County District Court. Sixty-year-old Thomas Guy Henderson was found guilty of two counts of first-degree murder by a jury of his peers for killing 48-year-old Tammie Devore and her son, 30-year-old Karl Devore, at their residence in Glidden. He was sentenced to life in prison on both counts. Henderson attempted to appeal his case to the Iowa Court of Appeals, but they declined to review it further. A similar appeal to the Iowa Supreme Court was also denied in 2017. Henderson initiated a postconviction relief request in March 2018 that argues the sentences should be thrown out due to ineffective assistance of trial counsel and lack of evidence. The Iowa Division of Criminal Investigation (DCI) laboratory linked Henderson to the crime after DNA found on the knife used in the murders matched his DNA profile. The postconviction relief trial is scheduled to begin on Tuesday, Oct. 26. Henderson is currently serving his life sentences at the Iowa State Penitentiary in Fort Madison.