Qld murder victim replied to sex ad

A prostitute and her unemployed partner arrested over a Gold Coast murder lured robbery victims with online advertisements for sex, detectives allege.

The 33-year-old mother of three and her 28-year-old partner were arrested on Wednesday over the murder of Gold Coast man Mark Emanuel Spencer, found bludgeoned to death on October 1.

Mr Spencer, 37, sustained severe head injuries at his Coomera home in what police have previously described as a targeted attack.

Detectives found a bloodied tennis racquet and broken baseball bat at the scene.

Mr Spencer had replied to an advertisement for sex on the classified website Craigslist, falling victim to the couple's ongoing ploy, Detective Superintendent Dave Hutchinson said on Wednesday.

"They had a plan together to go to the client's residence and actually rob that person," he told reporters on the Gold Coast.

"We believe that this has probably occurred on a number of occasions and because of the circumstances the victims would have been very reluctant to report that to the police."

The couple used the likely embarrassment of victims as a way to ensure their ploy could continue, he said.

Det Supt Hutchinson urged previous victims to come forward, but said police were unsure how long they used the ruse.

Mr Spencer knew the woman but wasn't aware she was the prostitute responsible for the advertisement, he said.

The pair have been charged with murder and robbery with violence over Mr Spencer's death, as well as charges stemming from a robbery in Holmview, south of Brisbane, the night before the murder.

The two will appear in the Southport Magistrates Court on Thursday.