The boy was found dead inside the vehicle parked outside Hambledon State School in Cairns at 3:15pm on Tuesday.
He had been picked up at about 9:30am that morning and police continue to investigate what happened in the six hours before he was found.
It is policy for the boy to have been buckled in to a car seat when he was collected by the driver of the Goodstart Early Learning bus, centre boss Julia Davison told the Courier Mail.
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“We expect he would have been strapped into a car seat when he was picked up, that’s our process,” she said.
“We don’t know what happened, we know we got a set of policies and procedures that are very clear about what our educators on the bus should do.”
Their focus is on where exactly the bus went during that period – as the driver travelled for other appointments that day – and whether the boy was on it the entire time.
The boy was found dead inside a childcare centre bus during a heatwave, leaving the driver in “shock and distress” and police working to find out “exactly what has happened”.
It’s believed the childcare centre he was being taken to was just down the road from the school.
The devastating find was made on a bus in the carpark outside Hambledon State School in the southern suburb of Edmonton at 3.15pm on Tuesday. The bus itself is one of the crime scenes.
Goodstart’s centre at Edmonton is closed and bus services have been temporarily suspended since the incident.
“We have decided, as a precaution — this has been a very difficult decision for us to make — to not use our buses from later today,” Ms Davison told reporters on Wednesday.
“We want to be conservative, we want to actually understand and make sure that we have got every possible procedure in place, that all of our staff have received refresher training.”
Goodstart Early Learning has been contacted for comment.