Warning: This article contains references to mental health and suicide. It also contains details readers may find distressing.

An inquest is being held to determine whether a man killed his mother before placing her in the driver’s seat of her car to stage that she was behind the wheel during a crash.

Tracee Ann Grosvenor, 58, and her son Ethan Grosvenor, 27, crashed into a tree on Langhorne Creek Road, about 60 kilometres south-east of Adelaide, on December 3, 2022.

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Opening the inquest in South Australia’s Coroners Court today, counsel assisting the coroner Darren Evans said the court would ask Deputy State Coroner Naomi Kereru to determine if Mr Grosvenor killed his mother.

Mr Evans said the court would also seek to determine whether “safety issues” had been identified and addressed after Mr Grosvenor took his own life 11 days later.

He told the court Mrs Grosvenor was in the driver’s seat when police arrived at the crash scene early on December 4, but that DNA evidence later showed her body had been moved.

“Her lower legs and body were in the driver’s side, with her upper body lying across the centre console into the passenger side,” Mr Evans said.

“Members of SAPOL’s Major Crash Section formed the view that the injuries Mrs Grovsenor had sustained were inconsistent with the dynamics of the collision if she was seated in the driver’s seat.

“DNA evidence subsequently effectively confirmed that Mr Grosvenor was driving the car at the time [of the collision] and that after [it] he had picked Mrs Grovsenor up over his shoulder and put her into the driver’s seat.”

A woman with curly blonde hair smiles for the camera.

Tracee Ann Grosvenor died in December 2022. (Supplied)

Mr Evans also said that, after the crash, an “independent witness” came forward and said she had seen the same car pulled over by the side of the road about 10:30pm on December 3 and that “Mrs Grosvenor was in the passenger seat, appearing distressed”.

Mr Grosvenor sustained minor injuries in the accident and was detained under the Mental Health Act.

The act gives South Australian doctors the power to lawfully treat and, in certain cases, detain people affected by mental illness.

Son died days after crash

Mr Evans told the court that Mr Grosvenor took his own life on December 14, 2022, after leaving the waiting room of the Adelaide Dental Hospital on North Terrace in the CBD.

The inquest heard that Mr Grosvenor was supervised by his occupational therapist, Rachael Rolla, at the appointment because he was at “risk of absconding”.

A woman wearing a suit sits behind a large wooden bench.

Naomi Kereru will hand down her findings later. (ABC News)

Ms Rolla told the court the 27-year-old “asked to go to the toilet” and never returned.

“There was no policy at the time to indicate what to do if someone had asked to go to the toilet,” she said.

Ms Rolla said she was aware Mr Grosvenor had gone missing from the Adelaide Dental Hospital days earlier on December 9, 2022, while being supervised by registered nurse Jennifer Williams.

“At that point, did you consider: ‘Well, I know that he went missing before in this building, I really should pay particularly close attention to where he is about to go?'” Mr Evans asked.

Ms Rolla responded: “I didn’t think it was appropriate to follow a male to the toilet.”

The inquest heard that, since Mr Grosvenor’s death, changes had been made to the “protocols and procedures” that “governed” mental health patient trips into the community.

Two women stand in front of the Coroner's Court to speak with a media scrum.

Julie Chapman hopes the inquest provides answers. (ABC News: Eva Blandis)

Outside the Coroners Court today, Mrs Grosvenor’s sister, Julie Chapman, said she hopes the inquest can help achieve justice.

“The system has failed us. We feel like we’ve just fallen through the cracks,” she said.

Ms Chapman said Mr Grosvenor had a history of mental health challenges and had displayed violent behaviour towards his mother, but said mental health services had failed to intervene.

“We need mental health to be taken seriously; we need families to be listened to,” she said.

Ms Kereru will deliver her findings at a later date.