Police opened a preliminary investigation into the online leak of personal information involving 168 people, including President Lee Jae Myung and senior government officials, authorities said Tuesday. The National Police Agency said that it launched the investigation Monday after information from a passenger list for the presidential aircraft was found posted online. The exposed data included passport details and other sensitive personal information. Authorities believe the leak may have involved an outside party. Those affected include Lee and first lady Kim Hea Kyung, Cabinet members, senior officials from Cheong Wa Dae and the foreign ministry, presidential security personnel and members of the press corps who accompanied the president on an overseas trip. The information exposed reportedly contained Korean and English names, affiliations, job titles, dates of birth, passport numbers and passport issuance and expiration dates. The file had reportedly been available on a paid security-related website since June 2, before Lee departed for the trip and remained accessible for months.