Adrian Chesters, 46, and his 14-year-old son, Nathen, were diving off Mersing in southern Johor. Alexia Alexandra Molina, 18, from France, also remains missing. Police said Thursday they still believe the divers will be found. “With their equipment, their full equipment and their experience, we believe there is a good chance we will find them alive,” said Cyril Edward Nuing, the district leader. Since then, diving has been suspended off the coast of Mersing, with the captain of the boat being held by police amid an investigation. Diving teacher Kristine Grodem, 35, who was training the team for her advanced licenses, was found safe after splitting from the group. An hour after the dive, it sounded the alarm as the team did not show up. According to naval officials, Grodem was rescued from a tugboat before being flown to the scene. Grondem told police the other three managed to surface. The search continued on Thursday morning after it was stopped late Wednesday due to poor visibility. The rescue effort involved two planes, 18 boats and nearly 90 people, including rescue divers. “We can not allow the diving to continue if the security measures are violated,” said Johor Sultan Ibrahim Iskandar. Malaysia reopened its border to foreigners on April 1 after being closed for more than two years during the Covid-19 pandemic. The Malaysian Immigration Department said more than 55,000 foreigners entered the country in the first four days after the border was opened.