A woman and her baby were enjoying a picnic at Hanlon Park in Stones Corner about midday on Tuesday when they were approached by a stranger.
Police said the man “approached them and poured a hot liquid onto the child, before leaving the scene”.
In the hours after the attack, the man then travelled to a church in Tarragindi and changed his clothes outside.
He then caught a rideshare car into the centre of Brisbane before moving onto Caxton Street.
Police canvassed those areas today.
Parents at Hanlon Park, where the attack took place, have been on high alert.
“It does make you a bit more aware, keeping an eye on who is around,” mother Sian Payne said.
The nine-month-old victim is recovering in hospital and continues to be monitored after the attack.
The baby took his first steps just hours before the attack. Today in hospital, he tried again, to his parents’ delight.
“He seems like his happy self again, which is really good because the last few days have been really, really hard,” the child’s mother told 9News.
The baby boy is expected to undergo a second surgery tomorrow and may need further surgery next week.
“We’re not sure if he’ll need skin grafts, laser, all that sort of stuff,” his mother said.
“We just wish we could take that pain away from him.”
“They were able to tell us that the burns on the side of his face, his lower arms and his legs should all be superficial and they’ll all heal properly,” his father said.
The baby’s mother wants to meet with the off-duty nurse who came to their aid in the park to thank her.
She has appealed for peole to come forward as the Child Protection and Investigation Unit investigates.
The man is described as in his 30s or 40s and of a proportionate build with tanned skin.
Police said he was wearing a black hat, glasses, a shirt and shorts and released two images they said were of him.
Neither the baby nor his parents can be identified due to Queensland’s child victims of crime laws.