The Melbourne man who killed his 11-year-old son at cricket training likely planned the killing and wanted to die in a suicide-by-cop, police say.

Moments before he died, 11-year-old Luke Batty asked his mother if he could spend five more minutes playing cricket with his father.

In those extra few minutes, his father killed him.

The estranged father and son were in the nets as junior practice was winding down at the Tyabb cricket ground on the Mornington Peninsula on Wednesday night.

It was the only place where Gregory Anderson was allowed to visit his son because he was subject to an intervention order, police say.

The 54-year-old had a history of mental illness and violent behaviour, but Luke’s mother, Rosie Batty, felt the cricket club was safe space.

“No-one loved Luke more than his father. No-one loved Luke more than me – we both loved him,” she said.

And Luke loved his father and felt safe around him too, she said.

“It was just a normal cricket practice and most of the kids and parents had gone,” she told reporters on Thursday.

“I had no reason to be concerned. I thought it was in an open environment.”

Minutes later, Luke collapsed in the nets.

It wasn’t until later when she was told Luke’s father wasn’t comforting the boy after an accident or injury – he was killing him.

Witnesses told police he struck his son in the head with a cricket bat. It’s believed he then turned a knife on the boy.

“We need to deal with that. Myself, my family, my friends,” said the grief-stricken mother.

“I want to tell everybody that family violence happens to everybody, no matter how nice your house is, how intelligent you are, it happens to anyone and everyone.”

Mr Anderson, of Chelsea Heights in Melbourne, was shot by police as officers arrived at the oval to find the boy lifeless on the ground.

The father had been threatening paramedics with the knife and was screaming “shoot me” as police sprayed him with capsicum foam.

Police say Mr Anderson then refused to drop the knife and rushed one of the officers until he was shot, once, in the chest.

The father also fought with paramedics and police as they tried to take him to hospital, where he later died.

There were no signs of an argument before the attack, but police believe Mr Anderson had been planning his son’s killing and wanted to die in suicide-by-cop.

Detectives noted he needed to travel 30km to the Tyabb oval, all the while armed with a knife.

He then waited to attack Luke when they were alone.

Ms Batty said she had previously considered moving back home to the UK, but wanted to keep her son near his school friends and have a relationship with his father, despite his spiralling problems.

Luke was an only child and shared a beautiful bond with his mother, said Gill Metzen, who knew Luke when he attended the Tyabb Childcare Centre for about three years.

“He was just a bundle of joy, he was a nice little kid,” she said.

She remembered how the boy’s father, however, had been homeless and once lived in his car.

Luke was in year six at Flinders Christian College and the school brought in counsellors and chaplains to support students.

Many others in the small community brought flowers to the cricket and football grounds on Thursday, including Wally Rachid and his 10-year old son.

“Shocking, absolutely shocking,” Mr Rachid said.

“It’s a big loss for the whole town, the whole area.”

Taylor Cuthbertson, 15, struggled to understand why it happened.

“It makes you so numb,” she said.

A Facebook page titled “R.I.P. Luke Batty” has been set up and attracted more than 40,000 likes by Thursday evening.

Cricket training was cancelled on Thursday as the community continues to grieve the boy’s death.