The knife-wielding young woman shot dead by police at a Hungry Jack's in West Hoxton on Tuesday had Asperger's Syndrome.
A condition related to autism that could have dulled Courtney Topic's response to police commands, in the brief time before she was killed.
On Wednesday her family told of their grief and pain at her loss.
Flowers arrived at Courtney Topic's family home, five minutes from where she was gunned down.
- Woman with knife shot by police at Sydney Hungry Jack's
- Cops shot 'within seconds': Confrontation ends in tragedy
Earlier, a neighbour mowed their lawn.
They are small gestures to help the family through what Courtney's father told 7News is overwhelming despair.
As the 22-year-old advanced on armed police yesterday, knife in hand, witnesses described her as being in a 'zombie-like' state.
Nearly an entire can of capsicum spray, did not stop her - one 40-calibre bullet did.
Experts say she may have had difficulty understanding police orders.
"We do not recommend shouting, which will make the situation worse, confrontation, lots of people giving orders," Asperger's Syndrome Specialist Professor Tony Attwoood said.
The 1997 police shooting of Roni Levi on Bondi Beach changed the way police treat and recognise the mentally ill.
He was also armed with a knife.
"It is important that they are trained regularly and refreshed regularly in how to deal with those situations," Professor Attwoood said.
A senior police officer has told 7News that while the young woman's death is tragic, this is not a Hollywood action flick where police have the luxury of aiming to wound someone.
If it gets to the point where lives are in danger, police are authorised to use deadly force, which means shooting at the largest part of the body, the chest.
Tom Lupton trained police for years on the rules of engagement.
"You only have seconds to act because if the person is under the effects of drugs or have mental conditions they dictate what's going to happen not the police," retired weapons trainer Tom Lupton said.