Tiahleigh's mother vows to continue fight for justice

Cyndi Palmer, Tiahleigh Palmer's biological mother (AAP)
Cyndi Palmer, Tiahleigh Palmer's biological mother (AAP)

A Kiwi woman whose biological daughter was allegedly murdered by her foster father in Brisbane says she will continue to fight for justice.

Queensland Police claim 12-year-old Tiahleigh Palmer was killed to cover up a sexual relationship with her foster brother.

Cyndi Palmer's pain is raw and because she knows nothing will bring Tiahleigh back, justice is her focus now.

It's almost a year since the school girl's decomposing body was found by fishermen on the banks of a Gold Coast river.

On Friday police began digging up the backyard of the foster family intrusted to look after Tiahleigh; investigators are looking for her missing school uniform and backpack.

Her foster father Rick Thorburn, a pallbearer at her funeral, is charged with her murder.

Police will allege Thorburn killed Tiahleigh to protect his 19-year-old son Trent, who allegedly had sex with her.

Trent faces incest charges, and his mum and brother were also charged in connection with Tiahleigh's murder.

It's emerged Tialeigh cried out for help a week before she went missing.

"She asked if she could stay with me and I said, 'I'm sorry I can't let you stay with me because I really don't know you for a start'," one woman says.

She claims Tiahleigh told her she was afraid to go home.

"She told me if she goes home she was going to get in big trouble, and that's why she didn't want to go home."

The woman says she called child services but the case worker dismissed the claims as lies.

But police allege six nights later, Tiahleigh was killed by her foster father.

Investigators are now building their case against the Thorburns.

Also under investigation is how Thorburn overdosed on pills while in police custody.

He's been moved from his hospital bed to a prison cell, where he's awaiting his next court appearance in December.

Newshub.