The Logan woman said she possesses emails notifying Tiahleigh's case workers she "hates it there" and warning she "has and will continue to run away", sent in February last year.
Ms Pemberton said Tiahleigh had run away more than 10 times in the last 10 months of her life. She expressed regret at not intervening. "I would have had her back in the following week, but I couldn't get her back," she said.
"Too late now. You've just got to stop it happening again."
The claim that Tiahleigh hated the house is at odds with comments from her grandmother, Sue Palmer, who told the Courier-Mail the 12-year-old had to option to leave the Thorburns but wanted to stay.
According to Seven News, Tiahleigh sought refuge with a school friend's relative, saying she was scared to go home. "She did tell me that if she did go home she was going to get in big trouble and that's why she didn't want to go home," the unidentified witness told Seven.
The woman claimed she notified the Child Safety Department, but said a case worker dismissed the child's concerns as "stories".
The woman also claimed Tiahleigh's foster mother Julene, who has been charged with perverting the course of justice in relation to the murder investigation, came to pick Tia up after finding out she was with the woman.
"Her response was she lies all the time and kids tend to tell stories," she told Seven News.
The same woman said she received a text message from Julene six days later saying Tia has "run from school again first thing this morning".
The text was reportedly sent the day after police allege Rick Thorburn murdered the troubled 12-year-old.
Thorburn had originally claimed he had dropped Tiahleigh off near her school the morning of Friday, October 30, telling investigators he was the last person to report seeing her alive.
Police are now expected to allege he murdered her the night before he claimed to have dropped her off, but still made the drive to the girl's school on the Friday morning without her.
Since being arrested on Tuesday of this week, the 56-year-old has been in police custody spending days in a Brisbane hospital after reportedly trying to overdose on pills.
He was placed in an induced come, but police confirmed he was conscious on Thursday afternoon and had been moved from intensive care to the hospital's secure wing. Once medical staff are satisfied he is able to be discharged, he is expected to be taken to the Brisbane Correctional Centre at Wacol.
Thorburn's wife Julene, 54, and one of his son's Josh, 20, were granted bail at their court appearances after being charged with perjury and attempting to pervert the course of justice. His other son Trent, 19, was refused bail on the same charges and an additional charge of incest.
The court heard Trent admitted having sex with Tiahleigh in a Facebook Messenger conversation with a cousin before her death and was worried she might have been pregnant.
Julene and Josh Thorburn will face court again on October 10. Trent Thorburn will remain in custody until his next court date on November 9. Rick Thorburn's matter will next be mentioned on December 21.
As the family await their court dates, investigators have begun digging up the yard of the family home in an "intensive forensic search". An excavator arrived at the Chambers Flat property this morning.
Police remain tight-lipped about exactly what they are looking for, but according to the Courier-Mail, it is believed to include Tia's missing school uniform and backpack.
"We will be looking for any evidence relating to Tia's murder and any of the other crimes with which the Thorburns have been charged," regional crime co-ordinator Detective Superintendent Kerry Johnson said.
"That will include any items, documents or DNA evidence. We will be looking for anything and everything."
The search comes as Tia's biological mother, Cindy Palmer, steels herself to front a media conference at Logan police station today. She is expected to thank police and the community for their efforts in bringing her daughter's alleged killer to justice.
- With AAP
