Monika Chetty was discovered critically injured and with her skin peeling off in bushland in western Sydney, on the evening of January 3, 2014.
She died four weeks later from complications following acid burns to 80 per cent of her body.
The 39-year-old, who was found with extensive acid burns to her face and body, had been estranged from her family since 2010 and was sleeping rough.
Evidence submitted to the NSW Coroners Court suggests Ms Chetty was doused in nearly eight litres of hydrochloric acid weeks before she was found.
Before her death, she told police she was curled up on a park bench in Liverpool when someone approached her for money and cigarettes, before dousing her with the chemical.
She said she attended hospital but there were no beds, but due to the extent of her injuries it is unlikely she was turned away, counsel assisting the coroner Christine Melis previously told the court.
Police also doubted Ms Chetty's version of events, believing she deliberately misled them about the location of the attack to protect herself and her family from reprisal.
Magistrate Elaine Truscott said the 39-year-old's death was caused by the burns and was the "result of homicide by person or persons unknown" in findings delivered at Burwood Local Court on Thursday.
After clinging to life for four weeks Ms Chetty, a qualified nurse at the time, passed away.
The inquest heard evidence Ms Chetty was "involved in activities and had associations which would give rise to persons having motive and opportunity to cause harm to her".
However, Ms Truscott was unable to determine how she was burned and who perpetrated the attack.
The former deputy state coroner urged police to continue investigating the unsolved homicide.
"I truly regret that this inquest has not been able to resolve the many questions about Monika's death and has brought no person to justice," she said.
Ms Chetty, a former nurse who became homeless after separating from her husband in 2009, was distanced from her family and had a significant gambling addiction.
She had told a social worker: "Someone poured something on me after I didn't give them money."
But when nurses quizzed her about previous burns she sustained over 2012 and 2013, she told them it was down to frying eggs and other cooking misdemeanours.
After acid was poured onto her she was still using public transport and begging for money in a hospital.
She repeatedly refused help from people while homeless and instead only sought cash, leading police at the time to believe she was under pressure to provide money to someone.
Green Valley Police Detective Superintendent James Johnson described the case as the "most baffling" of his career.
"In my 41 years in the police, this is most baffling. I cannot fathom the circumstances leading up to this," he told reporters at the time.
"She is covered in black marks. It's full-thickness burns.
"She would have been in absolute agony, in my opinion, and to survive this long is amazing."
A $500,000 reward offered by police in 2020 for any information leading to the arrest and conviction of those responsible for Ms Chetty's death has failed to produce any leads in the case.
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