Police have issued a blunt message to a man who poured hot liquid, believed to be coffee, over a nine-month-old baby boy in a random, unprovoked attack at a Brisbane park.

“Quite simply, get some legal advice,” Brisbane Detective Inspector Paul Dalton said.

“Give yourself up, go to the police station. This is not going away, and we will keep going until we find [you].”

Investigators released CCTV footage of a man running from the Stones Corner park, in Brisbane’s south, after a hot liquid was poured over the baby boy.

The baby was with his mother and another woman and her infant at Hanlon Park, off Regina Street, when an unknown man approached them about midday on Tuesday.

The man threw the hot liquid over the baby before running away.

The baby was rushed to the Queensland Children’s Hospital with serious burns and later underwent surgery.

“It is callous and cowardly when you look at the circumstances, particularly for us, who are parents, going to a park on a beautiful winter’s day in Brisbane, enjoying your time with your baby, a friend and their baby, and to be approached like this and attacked in this way must be terrifying for that person,” Dalton said.

“In 35 years of being a police officer, I’ve never come across a job where a child this young, in these circumstances, has been attacked. I can’t think of it. For me, it’s an incident that I’m not aware of happening.”