Bio

William Patrick Mitchell was born in 1971. By the early 1990s, Mitchell was living in Western Australia and working as a farm hand. He knew Karen MacKenzie, who lived with her three children at a rural property in Greenough, south of Geraldton.

Mitchell was a friend or acquaintance of Karen MacKenzie. Before the murders, he had reportedly been rejected by her. On the night before the killings, Mitchell had used a mixture of cannabis, alcohol, and amphetamines. At the time of the murders, Mitchell was about 21 or 22 years old. He later admitted responsibility for the killings and pleaded guilty to murdering Karen MacKenzie and her three children.

Murder Story

During the night of February 21 into the early morning of February 22, 1993, William Patrick Mitchell went to the rural Greenough home of Karen MacKenzie. Karen lived there with her three children: Daniel, Amara, and Katrina.

Mitchell had spent the previous evening using cannabis, alcohol, and amphetamines. Reports state that he arrived at the MacKenzie property in the early morning hours. Daniel MacKenzie, who was 16, heard a vehicle arrive and went outside to see who was there. Mitchell attacked and killed Daniel with an axe.

Mitchell then entered the home. Karen MacKenzie was asleep in the lounge room. Mitchell attacked and killed her with the axe. After her death, he sexually interfered with her body.

Karen’s two young daughters, seven-year-old Amara and five-year-old Katrina, were asleep in their bedrooms. Mitchell then killed both children. A judge later ordered that some details of the children’s deaths remain sealed because they were considered too horrific to be made public.

The bodies were discovered later that morning. The crime shocked the Greenough and Geraldton communities and became one of Western Australia’s most notorious murder cases.

Police investigated the scene and collected forensic evidence. A key piece of evidence involved hand lotion used by the killer. Fingerprints and chemical evidence linked Mitchell to the lotion and to the scene. Police later recovered the axe from the Greenough River.

Mitchell was arrested and charged about five weeks after the murders, on March 27, 1993. He confessed and took investigators through the crime scene, describing what he had done.

On September 8, 1993, Mitchell pleaded guilty to four counts of wilful murder, three counts of indecently interfering with a corpse, and one count of sexual penetration of a child under 13. On October 14, 1993, he was sentenced to strict-security life imprisonment with a 20-year non-parole period.

The sentence caused public anger. There were later appeals over whether Mitchell should ever be eligible for parole. He became eligible for parole in 2013, but his parole was refused. A second parole bid was refused in 2016. In 2024, Western Australia’s Attorney-General announced that Mitchell would not be considered for parole for at least another six years.

William Patrick Mitchell remains imprisoned in Western Australia for the murders of Karen MacKenzie, Daniel MacKenzie, Amara MacKenzie, and Katrina MacKenzie.