A man has died after he was critically injured in an alleged one-punch attack on a South Brisbane street.
The man had been on life support since Saturday after being punched by another man following an "exchange of words" between the pair about 10.15am on Melbourne Street.
Investigations suggest the 48-year-old alleged victim was walking along the street when he crossed paths with another man jogging in the opposite direction.
After they exchanged words, he was allegedly punched in the head and lost consciousness, falling to the footpath.
The alleged attacker then fled the scene in the direction of Merivale Street.
He is described as about 170cm tall with short dark hair, and was wearing black shorts with a red shirt tucked into them and white running shoes at the time.
Police have released CCTV footage of the man and are urging witnesses to come forward.
Anyone with information is urged to contact Crime Stoppers on 1800 333 000.