Her report says Mrs Wallis was once described as a vivacious, health-conscious and attractive woman - until she became depressed and suicidal about her marital difficulties and was admitted to hospital after overdosing on medication in 2001.
She became addicted to Diazepam, the anti-anxiety drug commonly known as Valium. In 2004, she stopped engaging with the mental health services, and the following year started refusing to leave the house.
In late 2005, Mrs Wallis and her husband worked hard to reduce the quantity of drugs she was taking - but this led to her spending time in hospital for withdrawal, and the couple separated soon after.
She moved in with a friend and frequently spoke of losing her dignity, her worsening state, and of taking her own life.
In August 2007, Mrs Wallis became upbeat - her family saw her dressed in street clothes instead of pyjamas for the first time in years.
But on August 21, she was dead.
For almost a year, the death was considered a result of her medication. But Wilson told a British TV documentary she had travelled to NZ to help a woman take her own life.
A police investigation was launched and found Mrs Wallis had been in contact with international euthanasia advocates. About three months before her death, she was given the name of a "doctor" who might be willing to travel here to assist her.
The woman was an assistant to a prominent right-to-die activist in the US, who claimed to have helped more than 100 people, including people who were not terminally ill.
Wilson flew to Auckland on August 15, 2007, and stayed in a motel. From a payphone, she spoke to Mrs Wallis several times.
Wilson subsequently admitted to the FBI, who interviewed her at the request of New Zealand police, that after six days she went to the house where Mrs Wallis was staying and watched her die.
She sat in the doorway as Mrs Wallis made all the preparations. She was there for two hours before finally taking away the evidence.
"I will say this: I was only a witness and friend who did not judge her choice ... She didn't want to die alone," Wilson said in an email to the coroner.
She said she had received $2000 from Mrs Wallis to cover her expenses, though $8000 in US currency has been found to have been withdrawn from Mrs Wallis' bank account, only $1300 of which was left in her bedroom.
Wilson was charged last year with assisting suicide, but the current NZ-US extradition treaty does not apply to euthanasia offences.
Mrs Wallis had sought help to die from the pro-euthanasia Dignity NZ Trust, which declined. Trustee Lesley Martin said there was a big difference between assisting terminally ill patients and taking money from someone with a drug dependency.
"It's a sad end for someone like Audrey who really needed more help, and a different kind of help than the one she ultimately received."
