A judge has ruled on what will happen to a teenage girl - earlier deemed unfit to stand trial - who allegedly helped kidnap, torture and murder Dimetrius Pairama.

The mentally impaired youth, who cannot be named, will be detained in a secure facility as a special care recipient.

Following a disturbing trial, both Ashley Winter and Kerry Te Amo were found guilty by a jury of murdering 17-year-old Dimetrius Pairama. The pair were jailed for life.

However, a third person was charged after Pairama's body was found by police in a rusty steel drum at an abandoned state house in Māngere on a cold, rainy night in July 2018.

The scene of the homicide in Mangere, Auckland. Photo / File
The scene of the homicide in Mangere, Auckland. Photo / File

This person was just 16 at the time and also accused of kidnapping and murdering Pairama.

But, she never saw a jury after the Court of Appeal ruled her unfit to stand trial.

The teen was found to suffer from mild intellectual disability and foetal alcohol spectrum disorder (FASD).

In his decision released today, Justice Timothy Brewer said what was particularly troubling was the risk of future violent offending. He noted the "offending was unusually cruel".

She displayed no empathy for Pairama and little remorse afterwards, he said.

"She took a young person to see Ms Pairama's body afterwards."

In the decision, Justice Brewer also noted the woman's ability to be deceptive.

"In her interviews with the police she knew the jeopardy she was in," he said before adding she had "serially denied" involvement.

Dimetrius Pairama, 17, was murdered in 2018. Photo / File
Dimetrius Pairama, 17, was murdered in 2018. Photo / File

Justice Brewer said special care "is not a punishment".

It was the most secure care option available and her interests will be assessed every six months, he said.

He noted she had not been convicted of any offence.

"She has been involved in offending which has attracted significant news media attention, but her impairment means she has not been found fit to stand trial.

"This factor reduces the legitimate public interest in knowing her name."

However, the judge specified should she subsequently be found fit to stand trial in
relation to this case then the suppression order would not apply to future proceedings.