Rosie Batty has broken down while saying she never believed her ex-partner would kill their 11-year-old son.

Under the strain of a second day giving evidence at the inquest into Luke Batty’s death, a tearful Ms Batty said she felt she was having to defend every decision she made about her son.

“Why am I having to defend the decisions I made about our son?” she asked.

“Isn’t it unfair that I’m having to be the one to answer for all this?”

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Greg Anderson murdered the 11-year-old by hitting him with a cricket bat and then attacking him with a knife while they played together in the nets following cricket training in Tyabb in February.

The 54-year-old was fatally shot by police.

Ms Batty said she had never heard of the term filicide until her son was killed, and never believed Anderson was capable of such an act of violence.

“Did I ever think Luke would get smacked over the head with a cricket bat and stabbed to death? Of course I didn’t,” she screamed.

“So don’t ask me any more about what I did and the risk I thought there was, because there was an ongoing, never-ending consideration of Luke’s safety, except he got killed, he got killed on a day everyone thought he was fine.”

Ms Batty said she had given the police Anderson’s address and wondered why they hadn’t acted on outstanding warrants and arrested him.

She said she thought: “Why haven’t you arrested him, I’ve given you his bloody address.”

Luke Batty pictured with his mother Rosie. Photo: ABC

Ms Batty on Tuesday described managing the relationship between Luke and his father as an “extreme juggling” act, and said she was often left exasperated by the actions of police and social workers.

“I was hoping someone was going to step in and help me protect Luke and take some weight off my shoulders,” she told the Victorian Coroners Court.

“I wanted support. I wanted other people to step in to make some decisions so it wasn’t just me facing Greg.

“The only suggestion they have is to have counselling.

“No one spoke to Greg. If he stopped being violent, I wouldn’t need counselling.”

Ms Batty has told the inquest she considered calling police when Anderson turned up at the cricket oval the night Luke died but decided not to, as previous attempts to have him arrested there proved traumatic and unpredictable.

Anderson went to the oval in defiance of a court order and in breach of his bail conditions in April 2013, but Ms Batty said police told her they could not arrest him because they did not have a warrant.

Ms Batty said she feared Anderson may have been contemplating killing Luke in a murder-suicide but did not believe it would ever happen in a public place.

She said she started believing Anderson could pose a risk to Luke when he showed the boy a knife and told him “this could be the one to end it all” in April 2013.

“I didn’t know if Greg was referring to his own suicide tendencies or if he would like to have a joint suicide,” she said.

“That image of him harming him couldn’t happen in a public place.

“It couldn’t happen at the Tyabb oval, but it bloody did.”

* Readers seeking support and information about suicide prevention can contact Lifeline on 13 11 14 or Suicide Call Back Service 1300 659 467.