The path to criminalising coercive control has been long and painful for Sue and Lloyd Clarke.
The grieving parents' four-year journey reached its destination on Wednesday when landmark legislation was passed in Queensland's parliament, marking a "mighty step" for women they hope will save lives.
In February 2020, their daughter Hannah Clarke and grandkids died in a shocking attack.
Hannah, 33, and her young children Aaliyah, Laianah and Trey, were set on fire in their car by her estranged husband Rowan Baxter.
More than four years later, Queensland became the second Australian jurisdiction to pass laws that criminalise coercive control.
"To know that the loss of our family will save other lives ... it doesn't make it better but it helps," Sue Clarke told reporters on Wednesday.
The Clarkes are now looking to push for coercive control laws to be embraced nationwide.
"This legislation is a mighty step towards Queensland empowering countless women across the state to fight against domestic and family violence," Mr Clarke said.
"Hannah didn't know she was in an abusive relationship because she wasn't being physically harmed.
"But now coercive control has been outlawed in Queensland, potentially saving the lives of many women and children."
Coercive control is a form of abuse where perpetrators display a pattern of manipulative behaviour designed to intimidate and isolate the victim.
The historic legislation was also welcomed by the family of Allison Baden-Clay, who was murdered by her partner in 2012.
Ms Baden-Clay's sister Vanessa Fowler said her sibling would have been "extremely proud" of the historic legislation being passed.
The new offence carries a maximum penalty of 14 years' jail.
"This isn't just poor behaviour, it's a crime and you won't get away with it," Mrs Clarke said.
"We will continue to speak out until coercive control is criminalised throughout Australia.
"We're hoping this important step in Queensland will inspire other states to empower and protect the women and children in their communities."
The Clarkes, who earned 2022 Queensland Australian of the Year honours, run the Small Steps 4 Hannah Foundation that educates children and supports victims and their families.
"Now we must work together to educate Queenslanders to recognise coercive control red flags," Mr Clarke said.
"We need to keep raising awareness of the dangers of controlling and psychological abuse, so victims are empowered to hold their perpetrators accountable."
Minister for Women Shannon Fentiman saluted the "tireless advocacy" of the Clarkes and Ms Baden Clay's family.
She expects the legislation to come into effect by the first half of 2025.
"This is a historic day," an emotional Ms Fentiman said.
"Our government understands how serious and harmful the offence of coercive control can be and this bill is the embodiment of a shift of our understanding of domestic and family violence."
Queensland Police will roll out a coercive training program for officers from July 2024.
Queensland now joins NSW as the only jurisdictions to have passed laws criminalising coercive control.
Meanwhile, an affirmative model of consent also passed as part of Wednesday's bill.
It requires free and voluntary agreement to participate in a sexual activity and expands the non-exhaustive list of circumstances where a person does not consent.
The laws criminalise tampering with or removing a condom without consent - called stealthing - to bring Queensland into line with most other jurisdictions.
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