Northern Coroner Nerida Wilson handed down her non-inquest findings into the Mount Isa caravan deaths of Nyobi Jade Hinder 7, River Jamie Hinder, 4 and Charlie Hinder, finding Charlie was responsible and he also tried to kill his estranged wife Katherine Hinder, who survived.

The caravan explosion at Deighton St on July 28, 2015 was one of the city's greatest tragedies and in her findings Coroner Wilson pieced together how it happened.

Katherine and Charlie were separated since May and Charlie was living in a caravan in the front yard with the children sleeping in the caravan when Katherine was on nightshift at Mount Isa Mines.

Katherine returned home from her night shift before 7am and Nyobi and River had not yet come back.

Katherine commenced preparing school lunches. At 7am Katherine's phone alarm started, her prompt to wake Nyobi and River.

Katherine stepped outside and approached the caravan and decided instead to send an SMS rather than knock to not disturb the neighbours.

As she went back inside the house to locate her phone an explosion occurred.

When Katherine recovered, the caravan was flattened and debris prevented her from getting outside the house.

She called Triple Zero and could see blood on her vehicle. Emergency services arrived, and an investigation commenced.

Initially investigators thought the explosion was caused by a gas leak but police later concluded Charlie had intentionally killed Nyobi, River and himself.

Katherine and Charlie met in 2005 when they were both underground miners at the mine and both used explosives in their daily working life.

The Court said while dating Charlie exploded a road sign in front of her using 'sausage style' power-gel explosive.

Katherine told Charlie she did not want any further involvement with explosives, Charlie assured her they were all gone.

In 2008 the couple moved to the mines in Rockhampton where they married and had their first child Nyobi

A year later Katherine located a tin full of ammunition and observed Charlie had been storing 'sausage style' explosives and commercial detonators.

She threatened to call police, he said he would get rid of them.

However the Court said it was the same commercial power-gel mining explosives used in the 2015 explosion which Charlie acquired at the Mount Isa Mine between 2005 and 2008.

In 2011 River was born and in 2013 the family returned to Mount Isa.

In 2015 the marriage began to break down and they separated.

Katherine later told police they had been experiencing emotional stress and that she wanted to leave but had not done so because Charlie had threatened self-harm and harm to her and the children.

The Coroner said she was satisfied Charlie's behaviour escalated as a separation became real and he used "covert and coercive controlling violence" including threats of suicide and self-harm, threats of harming Katherine and the children, discrediting Katherine's parenting to friends and family members, depicting himself as a victim, sexual jealousy and allegations of infidelity and monitoring her movements."

On March 31 Katherine reported an argument to police where he violently shook the couch she was sitting on hit her around the head with a pillow.

Katherine told police they both held firearm licences and had three firearms. Police placed Charlie in custody while they conducted an investigation and seized the firearms.

Charlie was released subject to conditions of the Domestic and Family Violence Protection Act and police filed an application for a Domestic Violence Protection Order though there was an absence of any indication that Nyobi or River had directly witnessed violence.

The order was granted for 12 months and Charlie attended counselling. He told police on April 23 there was "extreme tension" and "arguments [were] constantly occurring". Katherine told police Charlie 'shoved' her against a wall in the week prior, causing an injury to her nose that was still visible.

The Coroner said police erred by not investigating this matter further.

"After viewing the (police) body-worn footage I formed a view police interactions with Charlie were disproportionately focused on assisting him to avoid contravening the order, rather than invoking the protection it was meant to offer Katherine, Nyobi and River," she said.

In the days days leading up to the explosion Charlie posted messages on social media about depression and said "I only have love for my kids now, the other side of my heart is broken"

Just hours before the explosion, he posted a final message to Facebook: "I love my kids and can't let her evil take them from me....Goodbye everybody".

The coroner said no one who read or replied to the messages alerted the authorities.

"The last messages have a prophetic quality to them and, while Charlie's perceptions of himself as the victim are without basis, these messages demonstrate his mental state in the days leading up to his final actions. I am satisfied on balance, having considered the evidence before me, that Charlie was not the victim of domestic and family violence in the relationship with Katherine. Rather, he was the sole perpetrator of violence within the relationship," the coroner said.