THE unemployed stepson of murdered Queensland mum Hannah Clarke is making a legal grab for a slice of her estimated $3.6 million estate.

Isaiah Jesse Rowan Baxter last week quietly filed to sue Hannah's parents, Lloyd and Suzanne Clarke, over their daughter's estate - claiming he has been left without the funds needed for his maintenance, support, education and advancement in life.

The 23-year-old who lives with his mother and stepfather in North Lakes said in his claim to the Supreme Court that he had a "good relationship" with Hannah and that she "understood the struggles" he experienced with his father.

Hannah Clarke with her children (L-R) Laianah, Aaliyah and Trey.
Hannah Clarke with her children (L-R) Laianah, Aaliyah and Trey.

Mr Baxter said in his claim the Clarkes - who he considers second grandparents - own their own home, are "financially sound" and have already benefited from at least $1.5m in fundraising.

Mr Baxter says he now knows his father's estate has "no assets" and says the $4,244 from Rowan Baxter's superannuation and $40,000 in crime victims compensation he received is not enough, that he needs more to "build a future" and move on with his life.

In the claim Mr Baxter says the death of his family has been "incredibly traumatising" for him and he believes he will need ongoing psychological treatment for "many years to come".

In February after the brutal murder of Hannah and her children Mr Baxter adopted the family dog, Savannah, which has cost him about $3500 in vet bills so far, according to court documents.

Mr Baxter was just 12 when his father, Rowan Baxter, separated from his mother and moved in with Hannah.

Lloyd and Sue Clarke, parents of murdered mother Hannah Clarke. Picture: NCA NewWire / Dan Peled
Lloyd and Sue Clarke, parents of murdered mother Hannah Clarke. Picture: NCA NewWire / Dan Peled

In his affidavit Mr Baxter said he lived with his father and Hannah three days a week and that Hannah would frequently pick him up from school.

Mr Baxter said he continued to live part time with Hannah and Rowan, who had started a family of their own, until he was 17, when he arrived home from an outing and found his father had cleared out his bedroom and asked him to leave.

After that Mr Baxter lived full time with his mother and stepfather, moving to Hong Kong with them after he completed high school.

"When I returned to Australia, I wanted to continue my relationship with my half-siblings and Hannah, so as often as possible, I would visit Hannah and my siblings at her house when Rowan was not home …," Mr Baxter said in his affidavit to the Supreme Court.

"My relationship with Rowan was strained for my whole life as a result of his abusive and controlling behaviour towards me and also the abusive and controlling behaviour that I witnessed from him towards my mother and Hannah.

"I had a very good relationship with Hannah, as I think she understood the struggles I experienced as a result of my relationship with Rowan. I also had a good relationship with her parents, Suzanne and Lloyd Clarke, who I considered to be my second set of grandparents."

Hannah and her three children died on February 19 after her estranged husband Rowan ambushed the family on their way to school.

Isaiah Baxter, 22, (centre) the son of killer dad Rowan Baxter (left) with his stepmother Hannah whom his father murdered along with their three kids.
Isaiah Baxter, 22, (centre) the son of killer dad Rowan Baxter (left) with his stepmother Hannah whom his father murdered along with their three kids.

In a horrifying attack at Camp Hill, just metres from Hannah's parents' home, he jumped into their car and doused Hannah and the children with petrol before setting them alight.

All four died from their injuries. Rowan died from a self-inflicted knife wound.

Mr Baxter told the court, "I believe I will continue to suffer for the rest of my life" and that he made the application to assist in "building my future" and "moving on with my life as best I can".

Mr Baxter says in his affidavit he started to see a psychiatrist in 2013, that in April 2020 - after the tragic death of his family - his anti-anxiety and anti-depression medication was increased.

Mr Baxter told the court he filed the claim within days of learning his father's $1,823,258 life insurance would be paid to Hannah's estate and not to himself.

He said he had known since March he was entitled to make a claim on Hannah's estate but "chose not to" because he believed he would get his father's life insurance windfall.

"I believe that they both would have intended to provide for me financially in the event of their deaths" Mr Baxter told the court in his affidavit.

Isaiah Baxter, son of Rowan Baxter
Isaiah Baxter, son of Rowan Baxter

He says he believes his father failed to pay child support to his mother and to contribute to the cost of his school fees.

Hannah had modest assets when she died. She was living with her children at her parents house after having fled the rental home she shared with Rowan due to his violent and emotionally abusive attacks on her.

After her death Mr Baxter alleges Hannah's parents received an estimated $1.8m in life insurance for Hannah from insurer Clearview and the same amount from Rowan's policy, which stipulated it must go to Hannah, even after her death.

"To the best of my knowledge Hannah's parents are the beneficiaries of her intestacy," Mr Baxter says in his affidavit.

"To the best of my knowledge they also own their own home and are financially sound," he says.

" … following the events of February 2020 the Respondents were the beneficiaries of a Go Fund Me Campaign to raise money to assist with funeral costs, living costs … that campaign raised $1.5m … it is also my understanding there have been other fundraising campaigns which may have also benefited the Respondents."

If the case continues in court the Clarke family will be forced to reveal the size and location of assets in the estate.

Hannah Clarke with her children in happoer time.
Hannah Clarke with her children in happoer time.

The Clarke family set up a charitable foundation called, Small Steps For Hannah, and it aims to lobby government for coercive control to be recognised as a criminal offence.

Mr Baxter also stated in court documents that he is not studying, is not eligible for Centrelink as he was born in New Zealand and does not have a driver's licence.

Mr Baxter is the only surviving child of Rowan.

No date has been set to hear the case. The Clarke family have not filed a response to the claims.

Mr Baxter's mother, and the Clarke family, told The Sunday Mail they did not wish to comment on the matter.