A sadistic prisoner fantasised about dismembering his victims and pulling out their internal organs before luring an intellectually disabled inmate to his death.
However, a coroner has found corrective services officers could not have predicted Carl William Sedgwick Bloomfield's murderous plan.
Duke Allan Wayne Schafer was serving a three-year term in the Woodford Correctional Centre, north of Brisbane, for drug trafficking, supply of weapons and threats to kill.
Despite being intellectually disabled, Mr Schafer was placed in an overcrowded prison where 55 inmates were housed in a unit intended for a maximum of 35.
Considered a "prisoner of concern", Mr Schafer was housed along with Bloomfield, a career criminal who was known to have violent thoughts and fantasies.
"His thoughts escalated over a three-to-four-year period from fantasising about bashing people to imagining cutting people up, dismembering them and pulling out their internal organs," coroner Terry Ryan was told.
Doctors warned Bloomfield could be provoked by a word or even a look from fellow inmates.
On May 5, 2020, Mr Schafer accidentally triggered Bloomfield with an inappropriate joke about a photo of his daughters.
"Mr Schafer asked whether he could buy the photo and then laughed and Bloomfield took offence at this, and formed the view that Mr Schafer was a pedophile," the investigation found.
Despite Mr Schafer not having a history of sexual offences, Bloomfield decided the "kid f***er shouldn't have said what he said" and had to die.
The next day, he made a ligature by cutting the hem of a prison-issued bed sheet and lured Mr Schafer to the laundry, an area not monitored or covered by CCTV.
He strangled him with the ligature, shoving Mr Schafer's body under a bench.
Bloomfield then went to the exercise yard, changed his shoes and started his workout.
He later pleaded guilty to the murder and was sentenced to life in prison in June 2021.
Numerous investigations found Bloomfield to be a significant risk who took comfort in thoughts of inflicting pain.
"Key factors would've included his antisocial personality traits or disorder; ... his description of obsessive sadistic thinking, fantasy, rehearsing that fantasy in his mind," a sentencing report found.
"These fantasies were egosyntonic, that is, they gave him a sense of pleasure or relief that was very worrying."
After the murder, investigators found that despite court recommendations, Bloomfield had refused treatment programs and psychological care.
Queensland Corrective Services returned Bloomfield to the general prison population on December 6, 2019 and he was housed in the same unit as Mr Schafer without incident until the murder.
Despite the murder being "premeditated and planned", corrective services officers could not have reasonably predicted it, the coroner found.
"While there may also have been a missed opportunity to engage Bloomfield in drug intervention programs and counselling ... there is no evidence to suggest that it would have been outcome-changing." the report found.
Mr Ryan supported recommendations for increased supervision in laundry facilities and implementing changes allowing a single prisoner to use the laundry at a time.
