A man who robbed two sex workers in Brisbane is violent and likely to be a serial predator, police believe.
The man - described as Mediterranean with dark but greying hair - also appears to have accomplices, two other men helping him steal money from one of his victims.
The man met both women after getting their contact details from advertisements and engaged in sexual activity for about an hour before robbing them.
Superintendent Jim Keogh said police believed the man may have been targeting vulnerable sex workers for the past 12 months.
"We think there may have been similar offences committed by this offender, in particular involving single sex workers so we would ask those victims to also come forward," he said on Thursday.
"We are quite confident we will identify him but it's important that we do take him out of business sooner rather than later."
Supt Keogh said the man's "capability of violence" could not be understated considering one of the women had been thrown to the ground.
He said the man had also threatened the sex workers, who were Asian, telling them he'd go to immigration and federal police if they went to authorities.
But he said victims shouldn't be afraid to come forward.
"Certainly it's not an offence to work from home as these people are ... we are here to tell those victims we are here to support them and not to be deterred by the threats," he said.
The first sex worker, 30, was threatened with a knife after a man spent an hour with her at a West End unit on Tuesday night.
Another two men had arrived and threw the woman to the ground before rummaging through the unit.
The trio had stolen money and two mobile phones before fleeing.
On Wednesday night the man had stolen cash and threatened a 27-year-old sex worker at a Brisbane apartment.
He is believed to be around 30 years of age, possibly Italian, and about 175cm tall with dark hair greying at the sides.
