"It was a relief" – the same response outside court from Tia's biological mother Cindy Palmer, who had sat through allegations Trent Jordan Thorburn, 19, told a cousin he'd had sex with the schoolgirl days before her death and was worried she was pregnant.

In successfully opposing the metal fabricator's application for bail, prosecutors argued he had deliberately misled and lied to police throughout the 11-month investigation into the Logan girl's alleged murder.

Police will allege Mr Thorburn's father, Richard Thorburn, killed Tia at the family home on October 29 in an attempt to cover up his son's alleged crime.

The 56-year-old allegedly claimed to have dropped Tia at school the following day.

The accused killer was remanded in custody after his matter was heard on Wednesday morning in his absence, as he remained in an induced coma in hospital after collapsing in the watchhouse on Tuesday.

Police have refused to confirm reports he had swallowed pills but the Ethical Standards Unit was investigating.

Police prosecutor Sergeant Ellen French alleged a Facebook Messenger conversation between Trent Thorburn and his cousin two days before Tia went missing showed him making the admission of intercourse with his foster sister.

"He says he had sex with the victim on the prior Monday and he had only done so because she had threatened to kill his dog," she said, of a conversation that was allegedly handed over to police.

"The defendant said he was concerned about her being pregnant.

"The defendant further outlines the victim had spoken to his mother about it."

A friend of Tia's allegedly told police the 12-year-old had complained to Mr Thorburn's mother, Julene, about sexual contact with the defendant.

Mr Thorburn's defence lawyer John Ide called for his client to be granted bail on charges including incest, considering his age, lack of criminal history and the potential to spend more time behind bars awaiting a decision than an eventual sentence might impose.

"He's a young man with no criminal history whatsoever," he said.

"In my submission it couldn't be said he's an unacceptable risk of any of the things that's asserted by the prosecution."

Sergeant French told the court Mr Thorburn had denied on five separate occasions any involvement or sexual conduct with Tia and colluded with his family to mislead police.

"Eventually the defendant has admitted to the authorities that he had lied on multiple occasions in order to conceal the sexual intercourse between himself and Tiahleigh," she said.

A friend of Tia's also told police the young girl had approached her about a month before her alleged murder, saying "Trent tried to touch me", Sergeant French said.

Mr Thorburn has been charged with incest, perverting the course of justice and two counts of perjury relating to secret Crime and Corruption Commission hearings in July and September this year.

"The victim was put into the care and protection of this defendant and his family but rather than providing her with the care and love that she required as a child, this defendant betrayed her trust," Sergeant French said.

"He abused his position as big brother and took advantage of her and the consequences are a young life has been taken."

Mr Thorburn, an avid dancer, wanted to be released to live with his mother and older brother Joshua, 20, who were charged with perjury and attempting to pervert the course of justice but released after all four were hauled into Logan Central police station on Tuesday.

Mr Thorburn's entrance to a cramped, wood-panelled Beenleigh courtroom overflowing with purple shirts in support of Tia's mother, Cindy, captured every eyeball.

He was led into the glass-walled witness box in a brown, prison-issue T-shirt, his blond hair cut short at the sides and slicked back on top.

After a short hiccup, two dark-blue-shirted officers cracked the door to the off-triangular booth, sitting Mr Thorburn front right, from his perspective. The cuffs came off, along with an officer's hat placed in front of the trio.

Just after midday, defence and prosecutors handed up their arguments to Magistrate Pamela Dowse, who considered them for at least 15 minutes as supporters and the media waited in whispered all-but silence.

One supporter, not knowing the rules, took a photo of the accused, earning a court officer's reprimand.

Another two armed officers watched from the public gallery, removing their caps and standing in front of the crowd rapidly spilling out of the normally reserved space and onto the floor of the court.

Prosecutors argued Mr Thorburn was "highly likely" to interfere with witnesses and "would attempt in every way shape and form to evade and avoid every risk" of imprisonment, including by failing to show up to court.

Mr Ide argued these risks could have been negated by strict reporting conditions and a ban on contact with witnesses.

Sergeant French aired concerns the 19-year-old was a risk to other children through his job as a dance instructor but Mr Ide assure the court his client had quit in the lead-up to charges being laid.

After hearing the arguments from both sides, Ms Dowse kept Mr Thorburn behind bars, saying he was "not a candidate for bail at this point in time" but another application could be made in the future.

He will not have to appear for the case's next mention on November 9.

Supporters uttered a sigh of relief, with at least one stifling a jubilant cry of "yes!".

They had earlier filed into the court in a long line behind Ms Palmer, clad in a white T-shirt with the slogan "#JUSTICE4TIAHLEIGH".

Outside court, Mr Ide said he would consider applying to the Supreme Court for bail.

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