KUALA LUMPUR - Irish teenager Nora Anne Quoirin died from gastrointestinal bleeding which was likely caused by starvation and stress after she wandered into the forest in Negeri Sembilan, two kilometres away from the resort where she was staying with her family, Malaysian authorities said on Thursday (Aug 15).

State police chief Mohamad Mat Yusop told a press conference the missing 15-year-old, whose naked body was found on Aug 13 in a ravine, was unlikely the victim of foul play.

"There were no signs of rape," he said.

The teenager went missing on Aug 4, a day after her family checked into The Dusun eco-resort which is surrounded by lush tropical forest. Her parents, Maebh Quoirin and Sebastian Philipe, noticed the special needs girl was missing from the bedroom in the cottage and immediately lodged a police report.

"She had been dead for the past two to three days. Not more than four days," said Mr Mohamad, adding that the pathologist report stated that Nora died from gastrointestinal bleeding due to perforation of duodenal ulcer.

"Her intestine burst. Likely due to no food for long period and prolonged stress," he added.

Duodenal ulcers can be caused by the bacteria, Helicobacter pylori, or long-term use of anti-inflammatory drugs. Helicobacter pylori is found in unclean food and water, and can cause inflammation on the stomach's inner layer leading to an ulcer.

Ulcers will over time tear the stomach or duodenal wall, causing bleeding. Ulcers can also make a hole or perforation in the duodenal or stomach wall, causing an infection or swelling.

If left untreated, a bleeding ulcer can kill because of rapid blood loss.

Police dismissed claims on social media that the Irish teenager was a victim of violence, denying reports on the internet that Nora was raped by the indigenous Orang Asli.

"For the time being, there are no signs of violence or forced abduction," Mr Mohamad said.

Authorities will conduct more tests with samples sent to the Chemistry Department.

The state police chief said Nora's family, who were not at the press conference, could now claim the body.

Police had searched for 10 days in the forest and vicinity of the resort before finding the body by a stream, and it had to be airlifted due to the inaccessible location. Volunteer hikers found the body after authorities decided to narrow down the search location on Aug 10, circling areas they had covered in the early days.

The family has said that Nora was unlikely to wander off on her own given that she had holoprosencephaly - a congenital brain malformation - and that she was shy and wary of strangers.

The girl was sharing a room with two other siblings and reports said she was likely to have exited the room overnight through an open window.