Crown Prosecutor Danny Boyle said Simpson was hoping someone would find the child and take him.
"He gave him a hug when he got out of the car. At the park, he put his hand on his head and said he was sorry," Boyle said.
"He jumped in the car and drove off.
"He said he was hoping someone would find him and look after him."
Baden Bond is presumed murdered following his disappearance south of Brisbane in March 2007. Photo / Queensland Police The court heard that the couple called Baden "the devil's child" and often locked him in his bedroom with the windows spray painted black.
The couple would also reportedly leave the boy's nappies unchanged, with family members reportedly able to smell urine and faeces in his room.
Baden's body has never been found and there is no known cause of death.
The little boy's difficult life started in 2005, when he was born with methamphetamine in his system in an attempted home birth.
This led to the couple's other children being taken into state care, but they were returned to them just a year later.
Baden was last seen in March 2007 but it wasn't until June 2015 that he was reported missing.
Whenever someone asked the boy's parents where he was they claimed they had given him to relatives and didn't know where he was.
NSW community services came looking for Baden when the family was living in NSW.
The couple blamed Baden for the removal of his siblings and believed he was evil.
In 2016, when Simpson admitted to police he'd abandoned the toddler, he said Baden was difficult and "everything just got too much".
He said he was "fried" from his drug-taking at the time.
Simpson pleaded guilty to the manslaughter of Baden and Bond pleaded guilty to two counts of being an accessory to the manslaughter for keeping up the lies about Baden.
- With wires
