An investigation into the 2015 death of Brisbane schoolgirl Tiahleigh Palmer culminated on Tuesday with Queensland police charging Palmer's foster father with murder and arresting her foster brother for alleged incest.
Police confirmed Rick Thorburn, 56, was charged with the 12-year-old's murder at 2pm Tuesday and hours later confirmed her 19-year-old foster brother had been arrested for a number of offences, including perjury and incest.
No charges against the 19-year-old have been laid yet, while his mother and brother also remain with authorities to assist with police enquiries.
Tiahleigh Palmer went missing late last year and her biological mother has been persistently fighting to find out what happened to her daughter, whose body was found on the banks of a Queensland river.
So here's what you need to know about the 11-month investigation which has just had a major breakthrough.
When did Tiahleigh Palmer go missing?
Tiahleigh Palmer was reported missing on October 30 last year.
Palmer was last seen after being dropped to Marsden State High School at about 8.10am that morning. However she was not reported as having shown up to class.
Six days later -- on November 5 -- the Brisbane schoolgirl's body was found on banks of the Pimpana River.
Since then, her biological mother, Cindi Palmer, has kept up community awareness as the investigation continued.
Who has been arrested?
Rick Thorburn was taken into custody at Logan police station at about 11:30am on Tuesday and was charged with Palmer's murder hours later.
The 56-year-old has been denied bail and will appear in the Beenleigh Magistrates Court on Wednesday.
Palmer's 19-year-old foster brother has been arrested over incest, attempting to pervert the course of justice and two charges of perjury.
His mother, 54, and brother, 20, are still with police assisting with enquires. Police stressed the pair are not currently facing charges but are cooporating with authorities.
Hanson confirmed there are currently no further people expected to be taken into custody.
However, he would not confirm whether there were any other foster children currently in Rick Thorburn's care.
How did police make the breakthrough arrests?
The arrests on Tuesday come after police confirmed the car which was seized last week and labelled a "vehicle of interest" belonged to Tiahleigh Palmer's foster father, Rick Thorburn.
It is a 2009 blue-coloured Ford XR6 sedan.
Detective Inspector Damien Hansen detective inspector homicide said the investigation has been one of the most difficult cases he's ever worked on but praised the work of police and the community.
"We've had over 3000 separate lines of inquiry during this investigation," Hanson told media on Tuesday afternoon.