Crime Serial Killer Joseph Edward Duncan Dies in Prison at 58 The convicted murderer had been on death row for the 2005 killing of a 9-year-old boy By Cher Published on March 29, 2021 05:12 PM Share Tweet Pin Email Joseph Edward Duncan. Photo: Kathy Plonka-Pool/Getty Joseph Edward Duncan III died on death row in Indiana over the weekend. The convicted murderer died Sunday after previously been diagnosed with stage IV brain cancer, the United States Attorney's Office for the District of Idaho announced in a press release. Duncan, 58, was sentenced to death in 2008 and had been in custody on death row at the Terra Haute Federal Correctional Institution. He was found guilty of kidnapping and murdering 9-year-old Dylan Groene in Coeur d'Alene, Idaho, in May 2005 after also killing his mother, Brenda Groene, 40, her boyfriend Mark McKenzie, 37, and the boy's 13-year-old brother, Slade Groene, according to another press release from the Office of the District Attorney in Riverside County, California. Notorious Cleveland Serial Killer Anthony Sowell Dies in Prison at Age 61 He then kidnapped Dylan and his 8-year-old sister Shasta Groene, taking them to Montana's Lolo National Forest to torture them both before killing Dylan, according to court records, the District of Idaho press release said. Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories. That July, Shasta was rescued and Duncan was arrested when they were seen at a Coeur d'Alene Denny's restaurant. "This crime was horrendous and its impact on the families, the community, the jurors, court staff, our litigation team, and law enforcement were far reaching," acting U.S. Attorney Rafael M. Gonzalez, Jr. said in a statement. "While his death will not bring back the lives cut so tragically short or remove the indelible memories of his unspeakable acts, perhaps death will now allow space for some degree of healing, peace, and closure." Samuel Little, Serial Killer Who Confessed to 93 Murders, Dies at 80 Duncan confessed to killing the family as well as to killing multiple other children, including 10-year-old Anthony Martinez in 1997. Anthony's mother Diana said in a statement Sunday of Duncan's death: "The sun is brighter today, and my soul is lighter." "The world is a more beautiful place without the evil that is Joseph Duncan," she added. "God chose to make his end a long suffering and I believe that is fitting. The horror of his thoughts consumed him."