Two young men accused of bashing a man to death outside a primary school in front of hundreds of students during pick-up were his stepsons. 

Andre Szep, 63, was allegedly assaulted at a reserve behind Strathaird Primary School in Narre Warren South, south-east Melbourne, at 3.15pm on June 12. 

Liam Harnett, 22, and Connor Harnett, 21, allegedly beat Szep with fists and a pole or metal torch in view of hundreds of students as they knocked off from school.

Szep died in hospital on Thursday, and his stepsons remain in custody on charges of recklessly causing injury. They are expected to face court next month.

A family source told Daily Mail on Sunday that while they didn't condone the alleged attack, people needed to understand there was more to the story. 

The distraught source claimed the alleged incident followed 'years of suffering and abuse' for the family.

'No one did anything, no one helped [Liam and Connor],' they claimed.

'He [Andre] did all sorts of things to [the family]... stalking, surveillance, breaking into emails.' 

The source said Szep worked in IT, with an ABN registered under his name called IT Locum. It was active from 2010 to 2012.

It is understood the Harnett family is preparing for what they expect to be a 'messy' court case, but that they will fight for the boys 'all the way'.

Earlier reports said Szep's son - Liam and Connor's half-brother - witnessed the alleged attack, but the source claimed this was incorrect.

The Harnett brothers' parents, Kylie and Shane - who are separated - did not wish to comment when contacted by the Daily Mail.

Families of the 760 students at Strathaird Primary School received a letter from leadership on Monday offering support.

'You may be aware of an alleged assault that occurred in Strathaird Reserve next to our school last Friday afternoon,' it read.

'If your child witnessed the incident and you feel they need wellbeing support, please reach out to me... or the Assistant Principals and we will arrange it.'

One parent told the Herald Sun that many of the school children had witnessed the alleged assault.

'The kids were shaken up... They were terrified. I could see him lying on the ground and he couldn't get up. He appeared to be knocked out,' she said.

The parent said she also saw the incident and that some people shouted at the alleged attackers to stop.

'There were two men standing over him. They were yelling at him and hurting him with a pole or a metal torch. There were people yelling at them to stop,' she said.

'It was quite quick, then they jumped in their car and drove off. This should never have happened at a school.'

A Department of Education spokesman told the Australian Associated Press on Friday they were aware of a distressing incident that occurred near the school last week.

'Our immediate focus is on supporting the school community. The safety and wellbeing of students and staff is always our priority,' he said.

'Those who witnessed the incident have been offered wellbeing support and the school is working closely with families.'

There was no visible police presence near Strathaird Primary School last week, and no signs of the incident at the scene, including flowers or tributes.

The reserve, just metres from the school, is lined with trees and features a large oval popular with dog walkers and bordered by homes overlooking the park.

It also sits close to a children's centre.

Locals said a week after the attack they knew little about what happened, with one saying, 'It's Narre Warren'.