Joseph Edward Duncan

Joseph Edward Duncan is a serial killer, rapists, and pedophile. He killed 8 people throughout the span of his crimes.

Groene Family Murders

On the morning of May 16, 2005, after approximately three days and three nights of surveillance including the use of night goggles and late-night trespassing, Joseph Duncan III, 42, viciously attacked and murdered three members of a Coeur d’Alene, ID family.

Brenda Groene
Mark McKenzie
Slade McKenzie

Mark McKenzie, 40; Brenda Groene, 37, and the couples’ son Slade McKenzie, 13 were bound with zip-ties and duct tape in the family’s living room. The two youngest members of the family, Shasta Groene, 8, and Dylan Groene, 9, were also bound by Duncan and discretely placed on the lawn outside the family’s home. Duncan re-entered the home and murdered the three oldest members of the family using a framing hammer and a shotgun. Following the family’s massacre, Duncan kidnapped Shasta and Dylan, heading due east on Interstate 90 in a stolen Jeep. He crossed over the Idaho/Montana state line and disappeared into Lolo National Forest just outside of St. Regis, Montana.

Funeral home workers removing a body (source: Jesse Tinsley)
The Groene Family home (source: Jesse Tinsley)

The bludgeoned family was discovered by a distant neighbor who had not seen any activity around the property. Police were notified immediately and once they arrived on the scene, they discovered the slain family. They also discovered that Shasta and Dylan were gone.


On July 2, 2005, after 47 days of being missing, Joseph Duncan, a level III sexual offender, and young Shasta were recognized by employees at Dennys Restaurant in Coeur d’Alene, ID. Police apprehended Duncan and took custody of Shasta. She was quickly reunited with her father, Steve Groene.

A search party looks for the missing siblings
Surveillance showing Duncan and Shasta

According to a CBS News investigative report dated July 13, 2005, Shasta was able to recount to police and FBI investigators, in very vivid detail, where Duncan had taken her and Dylan, and what had happened during their abduction. She told investigators of how Duncan had repeatedly raped and sodomized both her and Dylan until ultimately killing Dylan and burying him in the woods. She explained Duncan had moved them to three separate campsites within the Lolo National Forest. Through concentrating their efforts, local, state, and federal investigators discovered Dylans remains not far from one of those campsites.

Shasta also told investigators the stories that Duncan had shared with her of how he had killed three other children in years prior.

 Connected to Past Murders

Joseph Duncan III was no stranger to authorities. In 1980, while a teenager, Duncan was convicted of sexual assault against another teenage boy in Tacoma, WA. and sentenced to 20 years in prison. He was released early in 1994, but that was rescinded in 1997 for violating the terms of his parole.

At the time of his arrest, Duncan was being investigated for a sexual assault against a child in Minnesota. While incarcerated for the Idaho killings, investigators were able to link Duncan to three murders that had occurred between 1994 to 1997 during the time of his probation.

Anthony Martinez

On April 19, 1997, the nude and partially decomposing body of Anthony Martinez, 10, was found in Indio, CA. The 10-year-old had been abducted by knifepoint from his neighborhood street, ten days before being discovered. He had been sexually assaulted and bound with duct tape. With no leads in the investigation, his case had gone cold.

Anthony Martinez

Sammiejo White & Carmen Cubias

Carmen Cubas (left) & Sammiejo White (right)

On July 6, 1996, Sammiejo White, 11, and her half-sister Carmen Cubias, 9, both disappeared from the Crest Motel in Seattle, WA.  Both of their skeleton remains were found in Bothell, WA on February 10, 1998. Both girls had been beaten to death.


Ultimately, Joseph Duncan III confessed to the kidnappings and murders of the McKenzie/Groene family in Idaho, the murder of Dylan Groene in Montana, the abduction and murder of Anthony Martinez in California, and the abductions and beatings to death of Sammiejo White and Carmen Cubias in Washington, though he was never convicted of the two girls murders.

While being interrogated, Duncan told investigators that he was smarter then they and he could have gotten away with the crimes if he wanted to, “but it had to end”. In his confession Duncan stated that the two children “taught me so much”. According to news articles, Duncan would spontaneously start crying and laughing. At one point, Duncan began sobbing and told the detective that he and Shasta had been through a lot and “all that matters is she’s OK. You don’t know how much danger she was in.”

Trial & Sentence

Court proceedings against Duncan lasted for several years because four states and the federal courts were all prosecuting Duncan for the crimes that he allegedly committed in their respective jurisdictions. For the Idaho trial, which took place in Boise, ID, videos on Duncan’s cell phone were admitted into evidence and played for the jury. One particular 33-minute video showed Duncan naked and physically abusing/sexually assaulting Dylan Groene who was naked and bound. In another video, Duncan can be heard shouting at a screaming Dylan; “The devil is here, boy, the devil himself…The devil likes to watch children suffer and cry.” Jurors were offered counseling because of having been subjected to the horrific evidence, according to one of a series of articles written by the Spokesman-Review, Spokane, WA.

Evidence: a letter from Sahasta to her father
Evidence: Duncan's jacket

Joseph Duncan III was charged and found guilty of 5 counts of murder, 4 counts of kidnapping, 1 count of sodomy, and other charges that included auto theft, drug possession, firearms, and parole violations.


He received 11 life sentences in addition to 3 death sentences. 


He was never charged for the murders of Sammiejo and Carmen.


From inside prison, Duncan maintained a blog with the help of people who supported him. You can view it here.


While serving out his sentence in Terre Haute, Indiana, Duncan was diagnosed with glioblastoma (brain cancer). He underwent brain surgery in October 2020 but declined chemotherapy and radiation. He died while incarcerated on March 28, 2021.

Over the years following her horrific ordeal, Shasta Groene has given minimal interviews. She became a mother and continues to live away from the public eye.

On an interesting side note, concerning the rural Idaho home of the McKenzie/Groene family. The house was later demolished by a crew of community volunteers. The land has since been left to regrow on its own. Out of respect for the family, the property was granted protection against further development or redevelopment indefinitely. 

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