The single mother packed the boy and five-month-old daughter Bella into her 2002 Holden Commodore on Thursday, December 11, 2012, and drove 170 metres down the road to Hungry Jack’s.

She ordered some takeaway food from the drive-through section at 4.43pm and then headed home.

‘‘During that journey Bella didn’t cry or make any noise, she was quiet,’’ Crown prosecutor Nicholas Papas, QC, told a Supreme Court jury during Ms Poole’s manslaughter trial.

‘‘She parks her car on the front nature strip, next to a little tree, and [her son] exits the front of the car carrying the food.

‘‘She exits the car from the front door carrying the drinks and she locks the car remotely.

‘‘The windows remain up, the vehicle is locked, and the baby is in the car, and it’s before five o’clock.’’

Bella died from heatstroke when locked inside the car on a day when it was 29 degrees at 3pm, 30.4 degrees at 5.30pm and stayed above 30 degrees until 7pm.

‘‘So, basically the baby is left in the car,’’ Mr Papas said. ‘‘She forgets the baby.

‘‘The Crown case is not that she deliberately left the baby. She completely forgot the baby was in the car.’’

Mr Papas said Ms Poole’s forgetfulness was such a serious breach of her duty of care that it amounted to gross negligence.

‘‘To forget the baby in these circumstances is so unacceptable, when one considers the duty of care, that she is guilty of manslaughter.

‘‘What she didn’t do on this day was take the baby out of the car, and that’s what caused the death, and any parent knows, anybody knows that you can’t leave a baby in a car with the windows up and the air conditioning off on a hot day.

‘‘And that’s the tragedy of this case ... a good mum forgets her baby and the baby dies; it’s dreadful.’’

Ms Poole told police she thought she had put the baby to bed before the drive to Hungry Jack’s. Her two-year-old daughter was alseep and being looked after by her grandparents when Ms Poole took the drive to the fast-food outlet.

Upon her return home, Ms Poole entered the house with the take-away food and drinks but not Bella. She put her keys on a hook in the hall opposite the baby’s bedroom before eating her meal with her son at the kitchen table.

Ms Poole's two-year-old dautghter woke up grizzly and was given some Hungry Jack's.

Ms Poole’s parents later left her and the children to go out to dinner. They walked past the Holden Commodore but did not see the baby inside.

Ms Poole bathed both the two-year-old and the the six-year-old before making a cup of tea and going out the back to have a cigarette.

She called a girlfriend at 6.44pm and they chatted for about 19 minutes before she hung up and walked down the hallway towards Bella’s bedroom at the front of the house.

She entered the room and became confused after seeing the baby’s bottle sitting on a table next to the cot but no sign of Bella.

Ms Poole panicked and frantically searched the house for Bella before ringing her sister, Megan Hillier, at 7.07pm, telling her the baby was missing and that she feared someone must have taken her.

She phoned the police and told them the baby had been kidnapped. No one had yet looked inside the car.

During her police record of interview, Ms Poole said she thought one of the policemen at the house had asked her: ‘‘The baby’s not in the car, is she?’’

The reference to "car" rang a bell for her so she grabbed her keys from the hall stand and ran outside.

She unlocked the car, opened the door, threw her keys on to one of the baby seats and realised, "Oh, my God, the baby’s in there" and started screaming, Mr Papas said.

Every effort was made to revive the infant but it was too late.

Ms Poole was later seen at the hospital in a private room cradling Bella and repeatedly telling her, ‘‘I'm so sorry, baby, I love you baby."

Ms Poole was charged with manslaughter but denied any wrongdoing, accepting she was morally responsible for Bella’s death but not criminally negligent.

Defence barrister Shane Gardner told the jury Ms Poole was not a child killer.

‘‘Sometimes decent, well-intentioned and well-meaning people do make mistakes,’’ Mr Gardner said.

‘‘Not in every case do we as a society need to declare that someone's criminally responsible.

‘‘By your verdict, Ms Poole's either freed of this legal burden, or she's forever to be known as a child killer, and I urge you to set her free, set her free in the sense of her legal responsibility because of course you know she'll never be truly free.’’

The jury on Thursday found Ms Poole not guilty of manslaughter.