Noah Zunde was just 22 months old when he was left in the back seat of his family car outside a childcare centre in Kyneton, Victoria for seven hours on February 19, 2015.
Noah’s mother inadvertently believed she had dropped her son off at daycare, and only discovered his body when she realised he was not in the centre.
The 22-month-old was still strapped into his car seat when his mother found him. Paramedics attempted CPR for several minutes, but he could not be revived.
Now, his death is set to be at the centre of an inquiry by the Victorian coroner into the deaths of children who were unintentionally left in cars.
Noah's case is the first of two that Judge Sara Hunchey will examine, in an inquest which will begin on Wednesday.
The purpose of the inquest is to explore the physiological and cognitive role involved in someone leaving their child in a car, in an attempt to prevent similar tragedies from occurring.
Monash University associate professor in psychology Matthew Mundy is set to give evidence during the investigation into Noah's death, and believes the toddler's mother was "severely sleep deprived" at the time of the accident.
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Dr Mundy said evidence suggested her lack of sleep may have contributed to a memory failure that is sometimes called 'forgotten baby syndrome'.
Noah's mother only realised she had left her son in the car when she arrived at the childcare centre to pick him up, and was told he wasn't there.
"I am 100 per cent sure she believed she had dropped him off that morning," a childcare worker said.
At the time of the incident, police said Noah's mother was "devastated" at her mistake.
"As you can imagine the family of this young boy are devastated by what has occurred so it's been difficult for us to try and piece together exactly what has occurred," Homicide Squad Detective Senior Sergeant Shane O’Connell told the Herald Sun.
"The mother was present when the young boy was located and she’s absolutely devastated by what has occurred. It's a very tragic set of circumstances," he said.
Noah's father posted a touching tribute to his young son on Twitter after his death.
"We lost our beautiful son today," Andrew Krespanis wrote on Twitter.
"I love him more every day. Forever. I'll always know I cherished every day. Every laugh, every adventure, every cuddle.
"Hug your children. Hug them and never let them go."