Slowly, we're piecing together the brutal reality of Hannah Clarke's final months.

This post deals with violence and might be triggering for some readers.

Hannah started dating Rowan Baxter when she was just 20 years old.

It’s then that the controlling and emotionally abusive behaviour began.

“We always had misgivings about him,” Hannah’s parents Lloyd and Suzanne told the Daily Mail, describing their former son-in-law as a “master manipulator.”

“He was always controlling, he ruined her relationship with everyone, even tried to get her away from us,” they said. “We’d go down to the coast and if they turned up and saw us there, they would go to another beach.”

WATCH: The horror of Wednesday’s events left Australia in mourning.

On Wednesday, Hannah Clarke and her three children – Aaliyah, 6, Laianah, 4 and Trey, 3  – were allegedly doused in petrol in their car at 8:30am in a quiet, affluent Brisbane suburb, and set alight.

The children died at the scene, and Hannah died later that night as a result of her injuries. The man who allegedly murdered them – Rowan Baxter – died from self-inflicted stab wounds nearby.

He reportedly purchased a jerry can of fuel from a nearby petrol station which he used to ignite the fire, and yelled at witnesses who tried to help to “stop putting it out” as his children burned.

On the December 5 2019, Hannah had moved out of the family home with the kids and in with her parents in Camp Hill, Brisbane.

7News reports Baxter’s behaviour towards his wife escalated after Christmas.

In early January, a Brisbane magistrate granted the police application for a domestic violence order to protect Hannah and the children. The Queensland police's Vulnerable Persons Unit had also been helping - offering both Hannah and the kids counselling.

Earlier this month, Baxter allegedly breached the DVO by contacting Hannah and he was served a Notice To Appear in court in March.

Brisbane Detective Inspector Mark Thompson confirmed in a press conference yesterday, "we have dealt with her [Hannah] on a number of occasions. We also referred Rowan Baxter to support services as well."

The couple owned a Crossfit gym together, and Hannah's parents said this was part of the problem. Baxter couldn't stand that Hannah would outshine him as a champion athlete. She'd won gold medals in trampoline, and had more qualifications as a trainer than him. They'd announced just before Christmas that the gym was closing down as Hannah made arrangements to separate herself from Baxter.

"He was jealous of her sporting success and when she beat him in Crossfit. He had a chip on his shoulder because he didn’t make it as an NRL player," said Hannah's mum.

In a GoFundMe set up for the family's funeral costs, Hannah's sister-in-law explained the Clarkes had "exhausted themselves" trying to "help Hannah escape this monster."

At the time of her death, Hannah was in a custody battle with Baxter - his Facebook a glittering shrine to his children and how much "Daddy loves you."

But Hannah's parents told the Daily Mail Baxter put on a facade to the outside world and convinced most people he had been "hard done by."

"He makes people think he’s a nice guy, then he sponges off them and burns them when he’s done with them, and moves on. He sponged thousands off us and Hannah," they said.

Hannah's brother Nat wrote on Facebook that his sister's romance truly turned into a nightmare about eight years in. After finally breaking free, his sister was excited for a fresh start telling him: "I’m so excited, this year will be great."

It was the last thing she said to him.

On Facebook, Hannah's friend Manja Whaley shared an eerie conversation she had with the 31-year-old.

"There was one thing he had said, really matter of fact, when you first got together 10 years ago and that was that 'he had told his ex-partner with whom he had a child, that if she was to leave him he would take the child and end his own life and that of the child'. He never did but you told me that this comment has always stuck in your mind," she wrote.

Manja and Hannah talked about her relationship after meeting at her gym in September 2019.

"We talked about the different types of violence including; financial abuse, sexual abuse, emotional abuse and you experienced all of them," said Manja.

"The decision made yesterday by Rowan to take your life and that of your three children [comes from] a belief system that you needed to be punished for leaving the relationship. This was not an act as a result of mental health issues or financial problems, this was a premeditated, deliberate decision to end your life and that of your beautiful babies," she continued.

On Boxing Day, Hannah had taken the kids to a park so they could see their father.

"You told me he picked Laianah up and started walking away, you asked him what he was doing and told him that your car was the other way, all whilst Aaliyah was distressed crying for her father to put Laianah down. Without any regard of the emotional damage to the children for taking Laianah away from her mother and her siblings, he proceeded to walk to the car and told you 'I told you, this is your fault'," wrote Manja.

Baxter had taken Laianah interstate for four days until police intercepted and brought her home.

Speaking to the Today Show this morning, Manja added that Baxter kept a watch on her social media, regularly threatened to punish her and her children (particularly if she refused sex), and only let her wear tights to the gym, because shorts were too "promiscuous."

Hannah Clarke had left her abusive relationship, and yet she still wasn't safe.

"For all those who knew Hannah or had even just met her once would know how much of a beautiful soul she was, her children were her life," wrote Hannah's sister-in-law Stacey Roberts online.

"All she ever wanted was happiness."

If this story 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.