Mum's fears left Tiahleigh with killer

Tracey Ferrier

The mother of murdered Queensland foster child Tiahleigh Palmer says she put her daughter into care to protect her from a violent domestic environment.

But Cindy Palmer's decision ultimately left the 12-year-old in the care of a man who would murder her, and involve his entire family in a complex plot to cover up the crime.

Tiahleigh's foster father Rick Thorburn was sentenced to a minimum 20 years in jail on Friday, after admitting he killed the girl because his own son, Trent, had been having sex with her and feared she might be pregnant.

Trent was ultimately jailed for incest, while Thorburn's other son, Joshua, and wife Julene, also served jail time for coving up the murder.

Ms Palmer says she still believes she did the right thing when she went to Queensland authorities, seeking a safer home for Tiahleigh, who was seven at the time.

She felt the "very severe" domestic violence situation she was living in at the time could get her killed, and wanted her child to be safe.

"... I actually went to the department for help because I realised that one day I was just going to die and (she) was just going to be left there by (herself)," Ms Palmer told the Nine Network's 60 Minutes program.

But having put her daughter into foster care, the separation compounded Ms Palmer's problems and she turned to drugs and ended up homeless.

She told of her concerns, a few years later, about Tiahleigh living with the Thorburn family, including Rick Thorburn's boasts about his previous criminal exploits and the fact there were teenage boys in the house.

"The first ever time that I met Rick, the first words that came out of his mouth were about how he was in a gang when he was younger and he was running guns and prostitutes. And he was proud of this," she said.

Ms Palmer said she'd received death threats over her decision to put Tiahleigh in care, but says she didn't kill her daughter.

"I've worked really hard not to be that person anymore, but I guess maybe it is a little bit of guilt because obviously I was meant to be a mother and I should have made better choices."

The interview included recordings of the Thorburn family finally admitting to police that they'd lied to cover up the schoolgirl's killing.

Josh said his father showed no emotion after murdering Tiahleigh and dumping her body in a Gold Coast river, where it was found six days after she went missing in October 2015.

"He didn't cry. He seemed quite assured and defensive of what he'd done and why he'd done it," he said.

"Obviously, it was to protect Trent."