The Coral Adventurer had only just begun its 60-day journey when the incident occurred.

WASHINGTON — An elderly cruise passenger was found dead after being left behind on Lizard Island, one of the first stops on a 60-day luxury tour around Australia.

The 80-year-old woman, who has not been publicly identified, was reported missing Saturday night after crew members aboard the Coral Adventurer confirmed she had not returned to the ship. A land and sea search was launched, and her body was discovered on the island Sunday. 

According to the Australian Broadcasting Company, Queensland police described her death as “sudden and non-suspicious.”

The Coral Adventurer had docked earlier Saturday at Lizard Island, a remote island 19 miles off Australia’s Queensland coast. According to the Coral Expeditions website, the island features a variety of excursions, including hiking, swimming and snorkeling.

According to the BBC, the woman had reportedly been hiking with fellow passengers on Saturday but is believed to have broken off from the group to rest.

Authorities are now investigating how the woman went unaccounted for when the vessel departed without her. The Australian Maritime Safety Authority told CNN it would be investigating the incident, including reviewing “the circumstances surrounding why the passenger may not have been accounted for during boarding.”

The woman had boarded the cruise just one day earlier. The reported $50,000 voyage was scheduled to take passengers around Australia, eventually reaching Western Australia.

Coral Expeditions CEO Mark Fifield told CNN the company was “deeply sorry” for the incident and has been in contact with the woman’s family. “We will continue to offer support to them through this difficult process,” he said.

The ship is expected to arrive in Darwin on November 2, where its crew will be questioned by authorities.