Tributes to the slain boy are mounting on social media as police call for witnesses to come forward after the boy’s father was shot by police on Wednesday night.

Luke Batty was bashed to death and his father died in hospital after police shot the 54-year-old in the chest at the sports oval on the Mornington Peninsula.

The boy was a student in Year 6 at Flinders Christian Community College and had just finished training with Tyabb junior cricket team at the time of the incident.

Executive principal Jill Healy called for the community’s ‘‘love and support’’.

Victoria Police Commander Doug Fryer said four local police officers arrived at the oval on Frankston-Flinders Road in Tyabb on Wednesday evening after ambulance staff called with reports that a boy had been bashed and sustained ‘‘horrific and brutal’’ head injuries.

Police confirmed they shot the 54-year-old Chelsea Heights man in the chest as he brandished a knife at officers, who initially tried to subdue him with capsicum spray.

The man later died from his injuries after being flown to The Alfred hospital in a critical condition.

Commander Fryer said a single fatal shot was fired by a police officer after police were unsuccessful in their efforts to talk the man down. He would not say if officers had access to stun guns.

"This was a dynamic, live critical incident. I won’t comment on their exact conduct," he said, adding the  Professional Standards Command would conduct the necessary investigation into the police officers’ conduct.

The boy was treated by paramedics but died of head injuries at the scene.

Police corrected earlier reports that the boy was 12 and said the Homicide Squad had taken charge of the investigation.

Commander Fryer told Fairfax Radio the incident was "complicated" and involved other locations.

It is understood a custody battle was under way between the parents.

The boy’s mother had been told of her son’s death and was distraught: "The mother has been advised, she was in the vicinity at the time but I can’t go into the details of what she saw,’’ Commander Fryer said.

"The death of a young child is always going to be horrific and I don’t know how the mother’s going to cope. She probably never will be able to."

Commander Fryer confirmed that the boy’s father and mother were estranged.

He said there had been multiple witnesses to the boy’s death and the shooting, including children and their parents.

Commander Fryer said the boy’s injuries were "significant" and "quite brutal".

He said police had spoken to witnesses at the scene, including some children, and called for others who police believed had yet to come forward to call CrimeStoppers.

A Facebook tribute page to the dead boy had attracted more than 200 comments and 3500 ‘‘likes’’ by 7.30am on Thursday, with some purporting to have witnessed the attack, saying there had been an altercation between the father and boy shortly beforehand. Police would not confirm whether this was true.

‘‘Such a waste of a young life - so much ahead of him,’’ one Facebook user said.

‘‘Oh my god my heart is breaking for his poor family, just one very sad ending of what seemed a normal day,’’ another user said.

Police cordoned off the oval, at Bunguyan Reserve in Tyabb, where a number of local sports clubs play, including the Tyabb Tennis Club and Tyabb Football Club.

Wayne Murray, who lives about 200 metres from the oval, said junior cricket and football teams were playing on the oval when the police shooting happened.

"I was having tea, I walked out the back door about 30 seconds after I heard the police [drive in]... things had gone quiet and I went to turn around and you hear a pop-pop," he said.

"It was absolute chaos once the first ambulance rolled in, a lot of police came in and then the air ambulance came in and landed on the oval.

The oval was cleared shortly afterwards.

Local Taylor Le Brun, 16, came to the oval after she learnt of the incident from neighbours.

"It’s unexpected so what could happen now? Because this has happened, what’s next? You can’t underestimate anyone now apparently."

With Jane Lee