Police in Victoria failed to pass on a gruesome death threat which had been made by Luke Batty's father, just weeks before he killed the 11-year-old in front of families at a public cricket pitch.

Greg Anderson murdered Luke on February 12 this year with a cricket bat and a knife in the Victorian town of Tyabb.

Anderson was shot by police at the scene and later died in hospital.

At the time, Anderson was homeless after being arrested and removed from a share house in the outer Melbourne suburb of Chelsea Heights.

A housemate of Anderson's had also taken out an intervention order against him after he threatened to cut off the housemate's head.

A week after police removed Anderson from the Chelsea Heights house, an officer rang Luke's mother, Rosie Batty, looking for Anderson.

Ms Batty told the police Anderson's new address, but the police did not pass on Anderson's threat to kill, nor the new intervention order against him.

A week later Anderson turned up to Luke's cricket practice and killed him.

Ms Batty said knowledge of the detailed death threat may have made her more aware of the imminent danger Luke was in.

"It's gravely concerning," she told the ABC's Four Corners program.

"A lot of us are very careless saying 'I could kill you, you know, you're driving me mad' or throw-away angry comments, but to actually say ... to decapitate someone. They're not light comments."

Victoria's Police Commissioner Ken Lay says because a coronial inquest into Luke's death is set down for October, he is constrained by what he can say in response to Ms Batty's concern.

"If ... what you're saying to me is right, the coroner will have a look at that," he said.

"But again, that may well be indicative of police members not being in possession of all the facts."

At the time Luke was murdered there were four warrants out for Anderson's arrest.

Rosie Batty arrives for the funeral service for her 11-year-old son Luke ( AAP Image: David Crosling )

Ms Batty and Mr Lay agree tragedies like Luke's death may be repeated unless there is better information sharing about high-risk offenders, both within and between the various agencies dealing with family violence.

"Things happen in such a fragmented fashion," Ms Batty said.

"They seem like isolated events, each statement you make to the police is a separate statement, each policeman you meet is a different policeman, each organisation is doing their own job with their own focus.

"No-one's taking an overarching look at everything that's going on together. No-one's looking at the complete picture."

This year the Victorian Government committed more than $30 million in extra funding aimed at managing high-risk family violence cases in the state.

The Labor Opposition has also committed to a royal commission into family violence if it wins power at Victorian elections in November.

Rosie's Story can be seen on the Four Corners website or on iView.