The heartbroken Hobart father of two children believed killed by their mother in murder-suicide in Melbourne will always be haunted by the knowledge he missed out on their final years.

Dominic Maher yesterday said he felt let down by a system that had prevented him from seeing son Matthew, 11 and daughter Melanie, 13, for three years before they died.

Police believe mother Kylie Fowler, 36, argued with the children’s older half sister Sammantha Fowler, 18, before killing all three children, setting fire to the house and committing suicide.

Mr Maher, of Chigwell, said he had spent years locked in court battles with Ms Maher, but when it consistently decided in her favour, he eventually moved to Tasmania.

He been preparing a video for his children explaining why he had lost contact with them which he planned to hand to them on their 18th birthday.

Breaking down yesterday, he said now he would never get the chance.

“I don’t know how you come to terms with something like this … it is too much to take in,” Mr Maher said.

He said he had only recently learned where his children lived, and was now consumed with questions about their final moments alive.

“I have heard these stories that Sam was stabbed and Matthew went to the her aid, and I just keep thinking about what was going through their minds.

“I just want to know if they suffered.”

Tragically, it is only now that his children have died that he is learning facts about their lives.

He did not know that Matthew was in a football club and it is only through tributes posted online by their friends that he is learning how well-liked they were.

But he said he has fond memories of their early childhoods and said he took comfort in knowing they knew how much he loved them.

“They were friendly, outgoing kids. Everyone loved them.

“Sammantha who was my stepdaughter was a lovely kid, she had to grow up too quick because she was always helping look after the other kids.”

Mr Maher is no stranger to tragedy, having lost his first partner and son in a car accident.

He and Ms Maher lost another son, Michael, to cot death and he said the death severely impacted on her.

“She was never the same afterwards. It hit us both hard.”

He said he planned to go to Melbourne as soon as the children’s bodies were released by the coroner, which he had been told would take about a week.

“I want to do everything right. If I go over there now I am in limbo, at least here I can work and keep busy.

“I know they have got friends there so I hope to hold a service so they can say goodbye, before bringing them back [to Hobart] for their funerals.”

Mr Maher said he was now trying to piece together the years of his children’s lives that he had missed out on.

“My photos are all outdated and now that the kids are gone they are all I have left,” he said.