"Detectives have worked through the night and will continue the investigation during the weekend to establish the exact circumstances leading up to the assault and death," Mr Sweeney said.
"Our condolences go out to the family of Mr Prue who are being supported by the police and Victim Support."
Mr Sweeney said as the matter was now before the courts, no further comment would be made.
He told the Herald yesterday officers were speaking to "a person of interest" and wanted to ensure the public that there was no danger to any other members of the community.
Earlier, social media users posted of seeing "multiple police units" at the scene. There were also reports of CPR being performed.
Ron Van Der Lem spoke to the Herald from outside the police cordon.
"I saw police cars coming from every direction, driving really fast," he said. "There's quite a few people gathered outside the cordon. Everyone's wondering what the heck is going on."
Cordons were put up last night between Richardson Tce and Hargood St.
The road is now open again but a section of the riverbank is still taped off. Police said they would reopen the scene later today.