Psychiatric hospital's response after Natalia Grace's parents tried to move her there

An upcoming documentary offering new insight into what happened to Ukrainian orphan Natalia Grace has revealed the psychiatric hospital's response when her parents tried to admit her.

Natalia Grace was adopted in 2010 by Indiana couple Michael and Kristine Barnett, but not long after Natalia went to live with the family, the parents began making accusations about her behaviour and her identity.

They alleged she was much older than she seemed, and the story caught the attention of millions of people across the globe in the documentaryThe Curious Case of Natalia Grace.

Now a follow-up to the original series, dubbed Natalia Speaks, offers Natalia's side of the story.

The new episodes reveal that as well as speculating about whether Natalia could actually be an adult instead of a child, mom Kristine allegedly told neighbors Natalia was trying to harm her and her family.

Natalia was accused of trying to poison her adoptive mom's coffee, and of carrying a knife into the couple's bedroom while they slept.

A neighbor spoke in the documentary about going with Kristine to look in Natalia's room after she allegedly 'sprayed furniture polish' into her mom's coffee.

Warner Bros. Discovery

"We found rubbing alcohol and matches..." the neighbor said. "And I was there, and I said [to Natalia] 'what were you planning on doing with these?'...

"And she said, 'I'm going to set the house on fire'."

In June 2012, Kristine and Michael admitted Natalia to a psychiatric facility, which she remembered as being 'super creepy'.

Natalia recalled being taken to a white room, which was empty apart from a bed with straps attached.

"Being in that room was creepy, because they locked me in there," Natalia said.

While Natalia was in hospital, a judge approved an emergency petition to have Natalia re-aged as an adult. As a result, she was moved from the children's section of the hospital to the adult's section.

After Natalia was re-aged, the psychiatric hospital contacted Kristine and Michael to share their thoughts on the girl - or 'woman' - they had admitted.

Warner Bros. Discovery

Legal expert Bath Karas recalled the hospital's response, saying: "[The hospital] contacts them, saying 'there's nothing wrong with Natalia'.

"They don't even see the need for medication or therapy, since they didn't consider her mentally unstable."

As a result, Natalia left the hospital and moved into a halfway house where she was exposed to 'smoking, drinking [and] cussing'.

In the documentary, FBI agent Veronica Maxwell suggested the Barnett's efforts to put Natalia into a psychiatric hospital were part of a 'multiple-pronged assault'.

"[They planned to] build a case against her as mentally defective," Maxwell claimed.

While their 'plan' to have Natalia committed to hospital 'failed', they did succeed in getting her age changed by law.

THE CURIOUS CASE OF NATALIA GRACE: NATALIA SPEAKS will premiere across three consecutive nights on ID beginning Monday, January 1, airing nightly from 9-11PM ET/PT.