Pallbearers, including accused killer Rick Thorburn, carry the coffin of murdered schoolgirl Tiahleigh Palmer during her funeral. Picture: Dan Peled/AAP

Back then, Rick Thorburn, 56, Tia’s foster father and accused killer, appeared to hold back tears as he solemnly carried her child-sized coffin, acting as a pallbearer.

He blended in to the crowd of purple, Tia’s favourite colour, which mourners had chosen to wear to pay tribute to the young girl. The colour also became a symbol of commitment to the desperate search for answers over what had happened to her.

His shirt read “in love memory of Tiahleigh R.I.P.” At the service, he comforted her grieving mother.

The truck driver turned food van proprietor and his wife had taken in Tia as a foster child while her biological mother, Cyndi Palmer, worked to get her life on track after struggling as a teen mum and spending time in the prison system.

Tiahleigh Palmer.Source:AAP

Tiahleigh Palmer.Source:Supplied

She lived with the couple and their two adult sons in their Chambers Flat home where Thorburn’s wife Julene, 54, also ran a home daycare service.

The eldest of the two boys, Josh, 20, was qualified to work as an assistant in the home business and had been unemployed in recent years while recovering from injury.

The younger son, Trent, 19, described himself as a dancer, metal fabrication apprentice, and classic car builder.

Police believe the teenager sexually abused Tiahleigh. He was denied bail on charges for incest, perjury and attempting to pervert the course of justice in court this afternoon.

In court, the prosecutor argued he “took advantage of (Tiahleigh) as her big brother and as a result her young life has been taken”.

The foster brother was concerned he had impregnated the child, the court heard. Police are expected to allege the boy’s father killed Tia to cover for his son.

A facebook photograph of Rick Thorburn and family Josh, Julene and Trent. Rick and Trent have been charged in relation to the murder of Tiahleigh Palmer.Source:Facebook

A Crime Stoppers tip led police to swoop on the family on Tuesday, arresting Rick, Julene, Josh, and Trent at various addresses in the Logan area.

Following police interviews Rick was yesterday formally charged with Tia’s murder. Trent, the youngest of Tia’s foster brothers, has been charged with incest.

Julene and Josh have been charged with one count each of perjury and perverting the course of justice.

All four family members are awaiting court, Trent’s today and Julene’s and Josh’s next month, though father Rick’s has now been delayed. The murder-accused was expected to face a bedside hearing at Brisbane’s Princess Alexandra Hospital, but is in an induced coma following a suspected self-harm attempt while in custody.

When his case returns to court, now scheduled for December, police are expected to allege the foster father murdered the girl in his car to protect his teenage son according to the Courier-Mail. Police will allege Trent sexually abused Tia.

Trent Thorburn was Tiahleigh’s foster brother.Source:No Source

Trent Thorburn, 19, has been charged with incest, perverting the course of justice and perjury in relation to the death of Tiahleigh Palmer.Source:No Source

Tia’s foster father and relatives have long been persons of interest throughout the 11-month investigation of the schoolgirl’s disappearance and murder, senior police sources told the Brisbane paper.

Less than a month after Tia’s death, the foster father published a post on Facebook saying the family had accommodation for one or two people in their “happy home environment on acreage”.

He described the residence as a clean and safe home.

The case has prompted the Queensland government to review the approval process for foster carers and working with children checks.

Acting Premier Curtis Pitt says both will be examined by extending a review already under way, with a report expected back early next year. “We will be very, very careful to ensure that the young people who are in our foster system as well as, of course, the broader child protection system are given all the protections,” he said.

Announcing details of the review, Child Safety Minister Shannon Fentiman confirmed the foster parents continued to run a child care business from their home after Tia’s death.

Tiahleigh’s mother, Cyndi Palmer at Beenleigh court on Wednesday where Rick Thorburn was due to appear. Picture: Liam KidstonSource:News Corp Australia

Tia went missing at the end of October last year. Her foster father was reportedly the last person to see her alive, dropping her off near Marsden State High school just after 8am on October 20.

Despite calls for action from her biological family, Tia wasn’t reported missing for six days. The delay was explained away at the time as taking care with concerns around identifying a child in care.

The same morning an alert was distributed by police appealing for help finding the girl, a trio of fishermen discovered her semi-naked decaying body on the banks of the Gold Coast’s Pimpama River.

The water and dirt had washed away any signs of what had happened to Tia, and police had few clues to work with while going about investigating how she had died.

Investigators were worried they may never solve the case.

Tia’s biological mother and grandmother were outspoken in appealing for witnesses and calls to Crime Stoppers from members of the public who may have seen or heard anything that could assist with finding out what happened to their little girl.

But her foster family was silent.

Foster father Rick Thorburn has been charged with murder. He is in an induced coma in a Brisbane hospital. Picture: Jack TranSource:News Corp Australia

Again speaking out, Tia’s grandmother Sue Palmer last night revealed her shock and anguish over the Thorburn family’s charges.

She said the news had “knocked the wind right out of my sails”.

“When it happens to your own it just is like a twisted knife in your heart,” she told A Current Affair on Tuesday.

“I’m just absolutely addled with thoughts of how she died, and that’s something that I really want to know.”

Ms Palmer criticised the Thorburn family’s behaviour following Tia’s death, which was made all the more alarming following yesterday’s allegations.

“They took pride of place at the funeral which I didn’t think they deserved and people treated them as though they were parents of long standing which they weren’t,” she said.

“It’s really really scary. It’s awful trying to raise little girls and boys nowadays. You can’t fix kids once you’ve wrecked them. You can’t fix Tiahleigh.”

Ms Palmer said she gained no relief from the arrests and charges, bringing her and the rest of Tia’s family closer to finding answers.

“To be really truthful it’s not a relief at all, it’s not even closure, it’s pain on pain,” she said.

Rick Thorburn remains in an induced coma and is due to face court on charges of murder and interfering with a corpse in December. His son Trent will face Beenleigh Magistrate’s Court on Wednesday charged with incest, perjury and perverting the course of justice. He is expected to apply for bail.

Thorburn’s wife Julene and other son Josh have both been charged with perjury and perverting the course of justice, and have been bailed to return to court on October 10.