Killer of 10-year-old Biddy Porter wanted to play 'serial killer' game day before murder

A coronial inquest has heard the person who murdered a girl in rural New South Wales had wanted to play a "serial killer" game the day before the murder.

Warning: This article contains descriptions of animal cruelty.

Bridgette "Biddy" Porter, 10, was murdered in July 2020.

In the Supreme Court in 2021, a person was found to have killed her but was not held criminally responsible for mental health reasons.

They are being detained in a forensic health facility.

A coronial inquest is underway at Lidcombe Coroner's Court in Sydney into Biddy's death and the circumstances leading up to the murder.

The girl's killer cannot be named for legal reasons and is referred to by the pseudonym XR during the inquest.

Fantasies of killing

State Coroner Teresa O'Sullivan yesterday heard that XR had fantasised about murder and had told their mother they thought about "killing people all the time".

The inquest was also told the person had killed six chickens and owned four knives and a tomahawk.

The mother of XR has continued giving evidence on day two of the coronial inquest, and told the hearing her child wanted to play a game with Biddy and another child the day before the murder.

"[They] wanted to play serial killers and [Biddy and the other child] didn't want to. I suggested [changing the name of the game and] calling it tips," the inquest heard.

XR's mother was asked if she considered letting Biddy's parents know that their daughter had felt frightened by the game and had fallen over while being chased.

"No," the witness replied.

She said she "never thought [my child was] going to kill her".

XR's mother finished her evidence by expressing her grief for Biddy's family.

"My heart breaks for them. I wish we could have all been together … knowing the pain we suffered for this little girl," she said.

"I certainly hope the parents find peace and comfort in these proceedings.

Stewart O'Connell, representing Biddy's parents, read to the witness an excerpt of notes that XR had made in a book about killing six chickens.

"Then [they say]: 'When it finally died, I hid its body and continued the indulging activity each day,'" Mr O'Connell read to the inquest.

"[Another child] came in when I was finishing off the chicken … [it took a lot of] willpower not to do the same to [the child]."

XR's mother told the court she was not aware of this, and said: "[They] didn't give me any details because I didn't want the details."

"[The chickens] were to be culled, so that was what was happening to them anyway," the witness said.

"However, mental health was never on my radar.

"I've never believed in mental health, I didn't understand mental health, so it didn't come up to me."

XR's mother told the inquest that, after hearing about the chickens being killed, she had been upset that the child had not asked permission.

Preventing future tragedies

Speaking outside court, Biddy's mother, Rebekah Keukenmeester, said it was hard listening to what was being said at the inquest.

"Some of the evidence we knew, but other parts of the evidence we didn't know about, so it's uncovering a lot," Ms Keukenmeester said.

"It's hard. It's very, very hard."

Ms Keukenmeester and Biddy’s father, Dominic Porter, lobbied for the coronial inquest to be held to examine the killer's mental health.

She said she believed Biddy's death could have been prevented.

"Definitely, and that's coming out in the inquest," Ms Keukenmeester said.

"That's all I wanted."

She said she hoped the inquest would lead to changes to prevent future tragedies.

"If people can watch out for warning signs, other parents, GPs, schools watch out for warning signs of mental illness or disturbed behaviour, then they can get help sooner and prevent something like this happening again," she said.

The ABC has been given permission from Biddy's senior next of kin, her parents, to use her name and image.

The inquest continues.