In 2018, teens Jack and Jennifer were murdered by their father. Their deaths were 'entirely preventable'.

Warning: This post deals with family violence and suicide and might be triggering for some readers.

On a Thursday evening in July 2018, 36-year-old Olga Edwards returned to her West Pennant Hills home to find that her 15-year-old son, Jack, and 13-year-old daughter, Jennifer, had been shot by their father. 

Today, an inquest found their deaths were "preventable". 

Watch: Women and violence: The hidden numbers. Post continues below.

The teenagers were killed by 67-year-old John Edwards, who stalked his daughter as she walked home from school that afternoon. Later that day, after emptying two rounds of bullets into his children, Edwards took his own life. 

Five months after her children's murder, Olga Edwards also took her own life.

On Wednesday, NSW State Coroner Teresa O'Sullivan found police failed to make reasonable inquiries after Olga reported instances of John Edwards' abuse and stalking in 2016 and 2017. 

Olga made her first police report in December 2016, where she described three instances to police of John assaulting Jennifer and Jack. 

Police "erroneously recorded" it as "domestic violence - no offence detected".

"Had the incident been categorised as assault or domestic violence, it would’ve appeared in the (firearm registry’s) system in relation to John’s suitability of holding gun," said O’Sullivan.

Gun registry staff, who were working without any formal training, also failed to recognise John Edwards' long pattern of domestic violence when they gave him various permits and a licence to shoot and buy pistols and rifles.

"To describe this as a tragedy is to import a sense of inevitability that nothing could have been done to change the outcome," she said.

"Instead, the evidence before this court plainly reveals the deaths of Jack and Jennifer were preventable."

O'Sullivan said that Edwards had formed the intent to murder his children by April 2018, when he acquired his second pistol. He then spent about a week organising the logistics, including hiring a car, getting a specialist to wipe his digital devices and writing letters to estranged family members.

She said it was difficult to imagine the pain Olga must have felt on July 5, 2018, when she found police at her home and her children dead.

"This moment was the crystallisation of the fear she had harboured as a victim of domestic abuse, as the mother of two children who had been the victims of domestic violence at the hands of their father, and as a wife and mother involved in protracted, acrimonious family law proceedings."

Olga and the children had disclosed the abuse and violence to multiple agencies, however, none of them effectively acted to assist them.

Similarly, NSW laws and regulations hadn't prevented Edwards obtaining the weapons to carry out his children's "meticulously" planned murders.

O’Sullivan also detailed previous unpublicised information about the murders, including that Edwards reloaded his pistol with another 10-round magazine during the shooting.

Listen: John Edwards and the family murder that shook Australia. Post continues below. 

O’Sullivan made 24 formal recommendations in her findings, including better domestic violence training for NSW police officers and regular audits of police reports to ensure they comply with best practice.

Despite the NSW Police's overhaul of the gun registry in response to the deaths, she said more was needed to address the "serious, systemic failures" present until July 2018.

She also called for better information sharing between the registry, police and Family Court to verify answers given by applicants, including whether they were subject to family law proceedings.

"Notwithstanding, the deaths of Jack and Jennifer serve as a stark reminder of the broader systemic problems that face too many women and children every day."

Police said they had implemented significant changes to systems and procedures regarding reporting and supervision of domestic violence incidents since July 2018.

"The NSW Police Force continues to identify ways to improve responses to firearms and domestic violence offences," they said in a statement. 

If this post brings up any issues for you, or if you just feel like you need to speak to someone, please call 1800 RESPECT (1800 737 732) – the national sexual assault, domestic and family violence counselling service. It doesn’t matter where you live, they will take your call and, if need be, refer you to a service closer to home. 

You can also call safe steps 24/7 Family Violence Response Line on 1800 015 188 or visit www.safesteps.org.au for further information.

If you think you may be experiencing depression or another mental health problem, please contact your general practitioner. If you're based in Australia, 24-hour support is available through Lifeline.

- With AAP

Feature Image: Supplied.