"Over a number of years, Ms Austen made contact with people in China and Mexico to arrange pentobarbital to be sent to New Zealand, and once picked up a package of the drug at a hotel in Hong Kong and brought it back to New Zealand," Feltham said.
She said a police investigation was begun after an autopsy showed Treadwell had pentobarbital in her system and a hand-written diary showing contact with Austen, who is the Wellington president of Exit International, an organisation that endorses euthanasia.
"We [the Crown] will show that Ms Austen gave Ms Treadwell an email address to contact a supplier to arrange pentobarbital to be delivered, which was intercepted by Customs.
"Police obtained access to Ms Austen's emails and saw conversations with Ms Treadwell and overseas [pentobarbital] suppliers."
Feltham said the day Austen was arrested, with a friend in a car park at Percy's Reserve, in Lower Hutt, she had in her possession two plastic bags containing quantities of pentobarbital.
The case is set down for three weeks.
- NZN