Who was Joseph Edward Duncan? Serial killer, 58, who slaughtered Idaho family and tortured boy, dies on death row
TERRE HAUTE, INDIANA: Almost 16 years after he terrorized Idaho, serial killer and child molester Joseph E. Duncan III has died on death row. The 58-year-old was diagnosed with terminal brain cancer last year and his attorneys disclosed that he did not have long to live.
According to a statement from prosecutors in Riverside County, California, Duncan died at the medical center near United States Penitentiary, Terre Haute, where he was on death row. He died just after 2:30 am on March 28.
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It was in March 2021 court filings that attorneys disclosed that Duncan was suffering from terminal brain cancer and that he had undergone brain surgery last October and was diagnosed with glioblastoma, stage 4 brain cancer. According to court records, he declined chemotherapy and radiation.
Revisiting Joseph Duncan's crimes
In 2005, Duncan was convicted of killing four members from Coeur d’Alene, Idaho. He kidnapped two children, Dylan and Shasta Groene, from the family’s home and tortured them in Montana before killing the boy. He had reportedly spotted the two children playing outside as he drove past their house on Interstate 90.
After holding them captive for several weeks, the little girl was only rescued after Duncan reportedly stopped at a restaurant in Coeur d’Alene and the staff recognized her. On May 16, 2005, authorities discovered the bodies of Brenda Groene, 40; her boyfriend, Mark McKenzie, 37; and her son, Slade Groene, 13, in their home along Lake Coeur d'Alene, outside the city of Coeur d'Alene
Duncan had videotaped several of his crimes against the Groene family which one investigator reportedly said "shook him to his core".
After Duncan's arrest in this crime, he was extradited to Southern California as his DNA was matched with the death of a 10-year-old boy named Anthony Martinez of Riverside County in 1997. According to reports at the time, Martinez was killed during the time Duncan was on parole for a rape charge in Washington. In July 2005, during his confession, FBI agents reported that Duncan said in an interview that the crime was “revenge against society again for sending him back to jail for a probation violation."
In addition to that, Duncan had also confessed to the murder of two young girls, Sammiejo White and Carmen Cubias, in Seattle in 1996. According to reports, after his release from prison, Duncan moved to Fargo and attended college. Shortly before graduating in 2005, he was accused of molesting a young boy on a playground in Minnesota. However, both those cases had gone cold by the time of his arrest and were not tied to Duncan until after his arrest in the Groene case. He is believed to have committed these crimes when he was released on parole in 1996.
In 1997, he was arrested in Kansas and returned to prison for violating the terms of his parole. On July 14, 2000, he was released from prison with time off for good behavior and moved to Fargo, North Dakota, which is where he joined college.
Relief for victims' families
Duncan's death from the long illness has brought some relief to the families of the victims. "The sun is a little brighter today,” Anthony Martinez’s mother, Diana, reportedly said about Duncan's death. "My soul is lighter. The world is a more beautiful place without the evil that is Joseph Duncan. God chose to make his end a long-suffering and I believe that is fitting. The horror of his thoughts consumed him."
Anthony’s father Ernesto reportedly, "While I would’ve liked to witness his execution, knowing he is now standing before God being held accountable for what he has done, what he did to my son, and the horrible crimes he committed to others, that is the real justice."