Cheznye Emmons, 23, was travelling with fellow Briton Joseph Cook, 21, through lush rainforest on Sumatra island, where many tourists go to see endangered orangutans, according to a police report into the incident.
The pair, accompanied by a third tourist, drank four bottles of local whisky called Mansion on April 20, according to the document.
Police said they were investigating whether the alcohol was laced with methanol, which is highly poisonous. They said they were awaiting lab test results before deciding whether to open a criminal case.
"We don't know whether the drinks were mixed when they bought them at the shop, or whether they have returned to their accommodation and mixed them with other things."
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The morning after consuming the alcohol, Emmons told staff at the accommodation where she was staying, in the Bukit Lawang area of Sumatra, that she had a stomach ache.
She was admitted to hospital in Medan, the capital of North Sumatra province, after checking out.
"On April 23, the owners of the accommodation... Received the news that (she) had died," the report said.
There have been many previous cases where methanol-laced alcohol has proved fatal in Indonesia.
In 2009, 25 people including four foreigners died after drinking methanol-laced palm wine on the resort island of Bali.