Mbyayenge "Robbie" Mafuta, the young man accused of killing his prison cellmate following a mental health episode in 2022, took a plea deal on Thursday that will likely keep him behind bars for six more years. Mafuta pleaded guilty in a St. Albans courtroom to voluntary manslaughter and aggravated assault in exchange for a 15- to 30-year prison sentence, with all but eight years suspended. Mafuta will receive credit for the roughly two years he has already spent in prison. The state initially charged Mafuta with second-degree murder for beating 55-year-old Jeff Hall, of Burlington, inside the cell they shared at Northwest State Correctional Facility. The December 2022 attack, which took place shortly after prison staff returned Mafuta to general population from mental-health segregation, left Hall in a coma; he died months later. Mafuta's public defenders had been pursuing an insanity defense, which has not succeeded at trial in Vermont in living memory. Mafuta, 23, lives with a serious mental illness and was homeless in Burlington until a series of property crimes eventually landed him in prison. He killed Hall while awaiting trial on those charges. Mafuta's path — from a charismatic immigrant teenager to a troubled young man suffering from hallucinations, paranoia and inadequate care — was the subject of a Seven Days cover story last year. [content-4] Wearing green prison clothes, Mafuta entered his guilty plea before an empty courtroom gallery Thursday morning. He admitted to punching and kicking Hall after confronting him for allegedly stealing other inmates' items — something Mafuta had told a psychiatrist by phone in the days following the attack, Seven Days previously reported. Franklin County State's Attorney Bram Kranichfeld, who became the county prosecutor shortly after the murder case was filed, told Judge Alison Arms that Mafuta will spend 25 years on probation after his release from prison. "The state recognizes that there is a strong component in this case of mental health, mental illness," Kranichfeld said. "Part of the sentence here is crafted to address that." Specifically, Mafuta will be required to participate in outpatient mental health treatment and anger management counseling, among other conditions. Kranichfeld also told the judge that members of Hall's family support the plea deal and plan to attend a future sentencing hearing. Hall's family has sued the private medical contractor that was responsible for treating Mafuta while incarcerated, claiming VitalCore Health Strategies clinicians did not properly…