A female tourist onboard a cruise ship sailing from Shanghai to Japan is believed to have jumped into the sea on the night of Sept. 10. The woman so far remains missing, the cruise ship operator told thepaper.cn.

The tourist was first confirmed missing at 9:15 a.m. on Sept. 11, and a surveillance camera showed the woman jumping overboard from a public area on the 15th deck of the cruise ship at 10:28 p.m. the night before, according to a statement from the cruise operator.

The report in thepaper.cn states that the Sapphire Princess, a cruise ship owned by Princess Cruises, left Shanghai International Cruise Terminal in Baoshan District on Sept. 10. The cruise was scheduled to head to Nagasaki, Japan and Jeju, South Korea in the course of a five-day, four-night trip.

The ship was in deep waters when the woman jumped. She was last seen onboard by another passenger at 7 p.m. on Sept. 10, according to Shanghai Daily.

The ship turned around to search for the woman before continuing on its scheduled voyage, according to thepaper.cn. However, ongoing rescue efforts and an investigation are both underway, Shanghai maritime authorities said.

A passenger surnamed Sun told thepaper.cn that the captain of the cruise had announced an emergency rescue around 10 a.m. on Sept. 11 (Japanese time). All passengers were required to evacuate their cabins. After a three-hour research, the captain confirmed that the missing passenger was not on the ship, said Sun.

Sun also reported that the missing passenger was said to be in her 60s. She was staying on the 6th floor of the ship with her son. Sun was skeptical that a passenger could have fallen overboard accidentally, as the fence surrounding the perimeter of the ship is around 1.4 meters high.

Last month, a Shanghai tourist was rescued from the sea by a fishing boat 38 hours after she was reported missing from a cruise ship. The 31-year-old woman, who was traveling from Fukuoka to Shanghai with her parents, was reported missing from the Mariner of the Seas at around 9 p.m. on Aug. 10. She was picked up by the fishing vessel at around 12 p.m. on Aug. 12.