Tiahleigh Palmer's foster parents have been arrested as a police investigation into her murder enters a "crucial stage".
The foster father, 56, was taken into Logan Police District Headquarters about 11.30am wearing handcuffs.
The slain schoolgirl's foster mother, 54, was expected to be brought in shortly after.
A police spokesman said two other men, aged 20 and 19, were in custody but not under arrest.
A car seized in the investigation into the killing of Logan schoolgirl Tiahleigh Palmer belonged to her foster father, police have confirmed.
Detectives seized the blue 2009 Ford Falcon XR6 sedan, labelled a "vehicle of interest", last week.
Investigations have been ongoing since the 12-year-old's body was found on the banks of the Pimpama River on the northern Gold Coast on November 5 last year.
The foster father was reportedly the last person to see Tiahleigh alive, when he dropped her off at school on October 30.
Fairfax Media is not suggesting any guilt on the part of the foster father.
Homicide Investigation Unit Detective Inspector Damien Hansen denied reports the man's version of events had not been corroborated with witnesses when he was first interviewed.
He refused to comment on suspects or persons of interest.
Inspector Hansen described the 11-month investigation into the girl's death as being "at a crucial stage".
"We'll be making further releases throughout the day," he said.
Tiahleigh's biological mother, Cindy Palmer, reportedly posted to Facebook on Monday revealing the car's owner.
Police spoke to Ms Palmer about the post, which she has since deleted.
Inspector Hansen said he was happy with how the investigation was progressing but media reports on the post "didn't help".
The foster father reportedly asked for all questions to go to the (now defunct) Crime and Misconduct Commission when asked by media on Tuesday morning about why the car was seized.
Detectives last week issued an appeal to anyone who saw the car in the area near Kerkin Road North at Pimpama about October 30 last year.
A $250,000 reward and indemnity for information remained on the table at that time.
It was six days between Tiahleigh failing to show up at school on October 30 and her body being found naked on the riverbank, where it had laid unnoticed for days.
Story courtesy of brisbanetimes.com.au