CINDY Palmer had no idea the tide was turning. It had been so long, too long. On June 17 she posted a collage of images on her Facebook page.

Her daughter’s white coffin. Pictures of Cindy in a purple T-shirt bearing her daughter’s name, holding a toddler in her arms, holding her partner’s hand, her face ashen.

Red eyes covered by sunglasses. In another she was strong, determined, standing in front of a row of buses, each bearing a larger-than-life picture of Tiahleigh in her cheerleading outfit.

The buses had been part of the ongoing campaign to draw out people with information.

“These pictures tell a few different stories,” she wrote.

“They tell of the break in a mother’s heart that can never be fixed, the love and bond that can never be replaced. The senseless loss of an innocent young lady, the unfairness and cruelty of a beautiful girl’s life taken horrifically, the unanswered questions and milestones missed, the siblings she will never know. It also shows the incredible strength of a determined mother who will not stop until questions are answered and justice is served.

“The amazing strength of a mother who must go on for her siblings while continuing to fight. They show the love and support of family and friends, strangers and people we have never met. The community united in such an unthinkable way.

“Now ask yourself why? Why (has) this not been solved? Why has no-one come forward and put a stop to this animal! I’m starting to lose hope … (I’m) unsure what else I, as a mother, can do. Please, if you know anything at all, come forward!”

She would never stop, she vowed.

ON SEPTEMBER 12, 2016, two relatives of the Thorburn family were called into the coercive hearings.

They were mother and daughter, people the CCC believed had intimate knowledge of the “family meeting” spoken about during the Crime Stoppers call.

In fact, it was believed that a meeting, held between Julene and the two relatives, occurred at their home.

They were given the opportunity to be truthful about what they knew. The mother knew her lies cound send her to prison. One of the women cried in the lift on the way down.

Three days later, one of those women was recalled for a second round of questioning. She told the truth. Both women would provide statements to police. The information they gave would prove invaluable.

As the CCC busied itself locking down witnesses to versions of events, secret listening devices were installed in the Thorburn home.

They were installed in August and would remain in place for nearly a month. They would prove very effective.

They caught Julene and Rick talking with their sons, planning and plotting.

“We have to stick to the same story of her going to school the next day and whatever,” Julene was heard instructing.

Two police officers flew to London to examine CCTV footage using a special, state-of-the-art program.

They would use it to follow the progress of a truck that had been driving the same route as Rick Thorburn on the morning of October 30 – both vehicles had gone by Marsden State High School.

By following the progress of the truck and its proximity to Rick’s blue Ford, they were able to determine that while Rick had driven by the school, he had not actually stopped.

On September 19, the CCC made its final move. Trent Thorburn was again called into the coercive hearing.

They knew he’d lied. They had evidence he’d molested his foster sister. Cornered, he confessed to some, but not all of what had been going on at the Thorburn house. He refused to take part in a recorded interview with police. The next day, Rick, Julene, Joshua and Trent were all arrested.

IT WAS the same female relative Trent had wronged, the one he’d sexually assaulted that night at the family camping trip, that he went to for help. It was October 28, two days before Tiahleigh would be reported missing, when he logged onto his Facebook and typed out a message. It had been years since that night she’d fled the tent she’d been sharing with the Thorburn brothers.

She’d forgiven and moved on. She hadn’t wanted to cause trouble in the family.

“Hey, are you free to talk? I really need to talk right now!” Trent wrote.

Sure, she’d replied. What’s up?

“I’m in trouble and I don’t know what to do! I know it’s going to be hard for you to believe but I’m telling the truth! Please, please help me. Mum and Dad went out on Monday to get horse feed and I was home doing my schoolwork and Tia was at home too,” he wrote.

“After Mum and Dad left she told me that if I don’t have sex with her she will kill Lewis my dog. She has been trying to get me to do stuff with her for a long time. Under sufferance of this I just couldn’t take the chance of Lewis getting hurt!

“I had sex with Tia without protection … but now she is saying she had stomach pains. I have changed from what I did to you because I know it is wrong and I still hate myself for that but I’m telling you the truth now and I need you!! Please!!!! I would rather kill myself than live with my family thinking I am some sicko and if you don’t believe me then I will, so please believe me because I don’t want to leave you all.”

He was terrified Tia was pregnant, he told her. He didn’t know what to do. If she was pregnant, he would go to jail. Nobody would believe him. He repeated that Tia, a 12-year-old, had made him do it. It was her fault.

Later, he would tell police he’d made this up, that he’d lied to make Tia look bad and himself look better.

“I just want the kid gone and out of my life but I also know she is a source of income for Mum and Dad as well and I can’t risk us losing money because she is gone,” he wrote.

He told her Tia had spoken to a friend of his, a girl named Tahlea, at a Father’s Day dinner. Tia had confided in Tahlea that Trent had been trying to “get her to do things”. Tahlea had confronted Trent and Trent had denied it, saying Tia had “problems”.

“I haven’t told Tahlea about anything though because I don’t want her to not believe me.”

The relative, Trent’s confidante, gave him sensible advice that night. She said his family would always support him, that the past had been forgiven but that he needed to talk to his parents about what was happening. She asked why he hadn’t gone to them when Tia had pushed for sex, when she’d threatened his dog. Why hadn’t he just told his parents? She pushed him to talk to them now.

“You just really need to decide what you’re gonna say leading up to it. Think about some of the questions they’re going to ask, and most importantly, be nothing but honest!” she wrote.

They continued the conversation through to the following day.

“Are you going to tell them?” she asked in a message at 5.49pm.

“I’ll do it tonight,” he wrote. “When both Mum and Dad are home.”

ON OCTOBER 29, Tiahleigh Palmer dressed in her school uniform, grabbed her purple backpack and jumped in one of the Thorburn cars for the short drive to school.

After classes, she went to drama club. And from there, she went to the Crestmead PCYC for a hiphop dance class. Her foster brother Josh helped teach that class, but partway through, Tia told him she was struggling, that she had a sore stomach.

Josh sent a text message to his mother Julene, asking her to come and collect Tia and drive her home. When Tia emerged from the PCYC, she seemed quiet, depressed.

“We’ll go home and you can have a hot shower and some Panadol or Nurofen,” Julene told her. It had been an odd day. Earlier she had received a text message from a family member.

“There is a serious problem,” the woman had written. “A major issue … I desperately need to talk with you.” They hadn’t talked yet. Julene had no idea what it was about.

Trent got home from work when Tia was in the shower.

He had something to say. Tia wasn’t around and he wanted to get the conversation over with before she appeared.

“I have done something terrible,” Trent told his mother. “I had a sexual encounter with Tia.”

He started crying.

“Oh my God, mate,” Julene said. “How could you let this happen?”

He trotted out the lie again. Tia had threatened his dog.

“I’m concerned because I sent some text messages to (the female relative),” Trent said.

Julene was by now connecting the earlier text message with the unfolding conversation. It was the female relative’s mother who had sent her the message. Both mother and daughter obviously knew about Trent and his 12-year-old foster sister.

She told him to go to his evening dance class. She would talk to his father.

“We will deal with it and work it out,” Julene said.

Trent left. Tia emerged from the shower and went into her bedroom. Julene went and found her husband.

“Trent came and told me about a sexual encounter with Tia,” she said.

The conversation was brief. They were worried Tia, with her sore stomach, might be pregnant.

“Trent can’t go to jail,” Rick said.

“We need to think this through,” Julene told him. “Deal with this properly, take this carefully.”

It was decided Julene would go and visit the relative who’d sent the text message and her daughter who’d been in touch with Trent. Before she left, she checked in on Tia.

Tia was in her pyjamas, sitting on her bed.

“Honey, you need to put yourself to bed,” Julene told her, adding that she had to pop out.

THEY sat in the living room. The relative handed Julene the series of messages between her daughter and Julene’s son.

“It’s important to get Trent help,” the woman said.

She said she wouldn’t report it. But that Trent should see a psychologist.

They talked for some time. Julene’s phone beeped with text messages as the women spoke. They were from Rick.

“It’s been long enough, hurry up,” he wrote.

“You need to get home so we can talk about issues.”

Julene arrived home about 10pm. Her boys weren’t far behind. She’d waited outside for them to pull in. She had a quick, quiet conversation with Josh about his younger brother. He was in some trouble, she revealed.

Then she joined her husband in the lounge room. The boys came in too. Rick told them to turn their phones off.

“Is Tia OK?” Julene asked.

“It’s all taken care of,” he told her.

“What do you mean by that?” Julene asked.

“Don’t ask any questions. You don’t need to know. I have taken care of it.”

Julene didn’t understand. She was speaking quietly, assuming Tia was asleep.

“Did Tia come out of her room?” she said. “Is she asleep?”

“I told you I have taken care of it,” he repeated.

Rick spoke to the boys next. He had instructions. They were to go about their day tomorrow as normal. He and Josh would go to the gym in the morning.

“Tia is no longer with us,” Rick told them.

“I hope you understand what that means.”

Then: “We have to protect Trent. We have to keep a story among ourselves that the next day she went to school.”

Josh immediately knew what his father was saying, even if Julene didn’t want to understand it.

His father had bragged about killing someone in his past. He’d told his sons he’d killed someone while he was a child in care back in New Zealand. Police have never found any evidence of this.

He’d even threatened to kill Julene if she ever left him.

Rick was matter-of-fact. Defensive, even. He was not concerned by what he’d done.

“I’ve made the right decision,” he said. “It’s already been done. I can’t change it.”

Julene walked by Tia’s bedroom and found the door was closed. Tia didn’t like being closed in, in the dark. She went to open the door.

“Don’t go in there,” Rick said.

Julene was beginning to feel alarmed.

“Why not?” she asked.

“I told you,” he said again, “it’s sorted. Go to bed. Tomorrow will be a normal day.”

Part 4: Killer finally brought to justice