Why Dubois was serving life sentence in Maryborough cell

The prisoner, who was found dead in his single-occupancy cell this morning, was one of Queensland’s most notorious killers.

Murderer Garry Dubois - who killed Barbara McCulkin and her two daughters in 1974 - has died in his cell at Maryborough Correctional Centre overnight.

Murderer Garry Dubois, who died in his Maryborough Correctional Centre cell overnight, had been serving a life sentence.

The 74-year-old and Vincent O’Dempsey had their appeal dismissed in 2018, after they were found guilty of killing Vicki McCulkin, 13, Leanne McCulkin, 11, and their mother Barbara McCulkin.

The duo were jailed for life, for abducting the mother and her daughters from their Brisbane home, before killing them in bushland near Warwick during the night on January 16, 1974.

Garry Dubois has died overnight.

Dubois was found guilty of raping and murdering the two sisters and was convicted of manslaughter against Barbara.

Queensland Corrective Services reported Dubois died overnight.

The trial heard Dubois may have been motivated to kill Barbara McCulkin due to fears she would implicate O'Dempsey in Brisbane’s Whiskey Au Go Go nightclub firebombing.

The firebombing had killed 15 people on March 8, 1973 – a year before the McCulkins’ deaths.

Dubois was expected to give evidence at an inquest launched into the fire alongside O’Dempsey, and pre-inquest hearings were held only a couple of months ago.

The 74-year-old was found dead in his single cell on Monday, June 7, 2021.

Dubois was found dead in his single-occupancy cell about 4.30am on Monday, June 7.

Officers and Queensland Ambulance Services attempted to resuscitate Dubois, however, were unsuccessful.

He was declared dead about 5.20am.

QCS and the Queensland Police Service are preparing a report for the coroner.