A judge has ruled that an Oelwein man charged with first-degree murder in the death of his girlfriend is mentally competent to stand trial. 40-year-old Toni Barrett, a convicted sex offender, is accused of killing 28-year-old Marie Ferrell of Oelwein in May. Her body was found in June, buried in a shallow grave in Waterloo. Barrett allegedly choked Ferrell, then hit her in the head with a hammer. During a hearing at the Fayette County Courthouse, a doctor testified that Barrett is competent to stand trial. The prosecution requested the mental evaluation after Barrett’s attorney sought an insanity defense based on the findings of another psychiatrist. Judge Steve Clark ruled that Barrett is fit to stand trial.