Police handling of a violent criminal who repeatedly breached parole was grossly negligent, a coroner said.
The man went on a destructive rampage in July 2009, which ended when he shot himself during a siege.
Shane Andrew Robinson, 32, stabbed a police officer on the Barrier Highway in South Australia and stole the officer's car.
He had been pulled over for questioning about suspected criminal activity.
Robinson ran over a pedestrian with the police car, then went to a homestead near Yunta and held a 75-year-old woman hostage.
She was bound and assaulted during the siege, before Robinson shot himself.
Coroner Mark Johns said Robinson's violent actions could have been prevented had police done their job properly and pursued him when he started behaving erratically weeks earlier.
Parole Board executive officer Kevin Hill told the inquest the Correctional Services Department failed to immediately tell the board about a serious breach a month earlier, when Robinson tried to strangle his girlfriend and failed to report to his Corrections officer.
The inquest heard police were alerted, but follow-up of the domestic violence report was inadequate and no attempt was made to identify the parolee involved.
The coroner was told Robinson was not adequately monitored because a Corrections staffer was on leave.
"This is an unsatisfactory situation and has resulted in significant changes within Community Corrections since and because of Mr Robinson's death," Mr Johns said in his findings.
Robinson's mother Jacqui attended the inquest and publicly apologised for her son's horrific crimes.
She said she felt the system let her son down.
"I would like to apologise to the victims of this terrible crime, leading to my son's death. I feel that the system has let my son down, let my family down and let the victims and the police and the community down," she said.
The inquest heard Robinson failed to complete anger management, alcohol abuse and domestic violence courses recommended by his parole officer.
He failed to make appointments with a psychologist, despite counselling being a release condition.
In 2002, Robinson took hostage a teenage boy at a house at suburban Netley, threatened him with an axe and held a knife to the boy's throat.
Robinson was shot in the neck by a STAR Force officer during that siege.
He spent time in hospital, then was sentenced to six years in jail with a non-parole period of four years.
The offender was released on parole in December 2007.
The Coroner concluded there was gross negligence by authorities involved in Robinson's management, particularly SA Police.
"There were opportunities to intervene in the management of Mr Robinson in a way that might have prevented the events culminating in his death, thus saving not only his life but the serious sexual assault of an elderly lady and the serious stabbing wounding of a member of the police force," Mr Johns said.
He said Robinson should never have been allowed to live with his partner and her teenage daughters, given his convictions for serious child sex offences.
Mr Johns also was highly critical of the SA Police call centre's handling of the report Robinson had attacked his partner.
"In my opinion call centre operators and their supervisors must be provided with domestic violence training, which instructs them on how and when to deal with allegations of domestic violence and emphasises that, where it is not known that the victim is actually safe and that cannot be ascertained adequately on the telephone, a police patrol should attend," he said.
"The failure by anyone at the SAPOL call centre to bother to inquire as the identity of the perpetrator of the domestic violence allegation is profoundly disturbing.
"It shows a lack of interest and commitment to the job of policing and keeping South Australians safe. It shows a narrow focus on the immediate task and a desire merely to get rid of a problem with a minimum of effort."
In a statement, SA Police said it was aware the coroner had made findings on the Robinson death and it would carefully examine the recommendations made.
The SA Opposition said former correctional services minister Tom Koutsantonis wrongly blamed the Parole Board over Robinson and the Yunta siege in 2009.
Opposition Leader Steven Marshall said Mr Koutsantonis should apologise.
"Minister Koutsantonis must be seriously regretting his comments in 2009 when he made it very clear that the unfortunate and horrific events surrounding the matter of Shane Robinson were fairly and squarely the problems of the Parole Board. The Coroner has given his findings today and has made it very clear that the Parole Board didn't have a role in this," he said.
Mr Koutsantonis said he still stood by the comments he made back in 2009.
"I think it's safe to say in hindsight that the inmate should have been left in prison. I'm taking the judge, jury and executioners who are here today who are telling me I've made a mistake, I haven't read the report I don't know what the findings are and it's pretty hard to make comments on findings I haven't read," he told reporters.