Police have arrested a 53-year-old woman in Sydney's west after her mother was found dead in an aged care home.
Emergency services were called to the facility on Evans Road in Rooty Hill just after 11:30pm on Thursday, following reports the body of a woman had been found.
Paramedics and police attended the scene to find an 84-year-old female dead inside the building.
"Police had cause to speak to a 53-year-old female who was present at that location," Detective Superintendent and Mount Druitt Police Area Commander Darrin Batchelor said at a press conference this morning.
"Due to those conversations and other evidence at the scene, that 53-year-old female was placed under arrest."
Police confirmed the 53-year-old woman was the deceased's daughter.
Detective Superintendent Batchelor said the younger woman "allegedly administered a substance to the older woman".
"We don't know exact[ly] what that substance is at the moment or whether that contributed to her passing last night," he said.
"It's really too early to determine what the motivation is at the moment, whether it was an assisted dying scenario, we really don't know.
"The 84-year-old female at the nursing home did suffer from a number of medical conditions at the time of her passing."
Detective Superintendent Batchelor said a nine-year-old boy was present on the night, who was now in the care of other family in Sydney.
He said police were examining evidence collected from the scene.
"The manner of the elderly woman's death will be a matter for the coroner to determine through toxicology reports and an autopsy," he said.
Detective Superintendent Batchelor said police were reviewing security vision and looking at why the 53-year-old woman was at the facility late at night.
"She has no history at all, no criminal history. We don't believe she's had any medical training at all," he said.
"The woman is being interviewed at this stage. She is being compliant with police."
A report will be prepared for the coroner.
