12th October 2023 – (Hong Kong) Student Matthew Tsang (17) from Diocesan Boys’ School, who went missing last Wednesday (4th), captured the attention of the entire city. Yesterday (11th), he was finally found safe and sound. During the search and rescue operation, Hong Kong registered land surveyor Lee Wai-pang utilised aerial photography surveying techniques to assist in the search. On the afternoon of the 10th, he used a professional drone to capture over 1,000 photos within the vicinity of Mouse Pit Stream. Approximately 10 of these photos revealed what is believed to be Tsang’s presence, showing him naked in the jungle.
Lee Wai-pang stated that he had been in constant communication with the volunteer search and rescue teams and based on their analysis of Tsang’s disappearance, he decided to conduct the photography in an area spanning a few hundred meters upstream and downstream of Mouse Pit Stream within a one-kilometer range. He took the opportunity on the 10th to arrange for the photography. Many of the photos were overlapping due to the height at which they were taken, ensuring that no area was left unsearched. Lee aimed to create a three-dimensional map for the purpose of locating the missing person.
He further explained that he employed an oblique photography method during the capture process. Since most people would search for missing persons using vertical aerial photography, they often missed finding individuals who were located within forests. In Tsang’s case, he was even found within a pile of grass. “By using aerial surveying techniques, we were able to spot him at an angle,” Lee stated.
After completing the photography on the previous day, Lee had time to carefully study the aerial photos on the evening of the 11th using aerial photograph interpretation techniques. He discovered that nearly 10 photos clearly indicated Tsang’s presence. Some photos showed Tsang’s entire upper body, while others only captured a partial view. “We couldn’t see the colour of his upper body clothing, but it appeared to be flesh-coloured, as if he was bare-chested,” Lee revealed. Tsang was found in a downward position from Mouse Pit Stream, approximately 10 meters away.
On the 8th day since the disappearance of 17-year-old Matthew Tsang, he was found in Mouse Pit Stream yesterday afternoon (11th) and was airlifted by the Government Flying Service helicopter for medical examination. Tsang was conscious during the transfer.
Lee Wai-pang mentioned that he had previously used aerial photography surveying techniques to search for a man surnamed Chung who went missing while paragliding on Lantau Island in 2018. Unfortunately, Chung was found dead on a hillside six days after his disappearance. Lee also acted as an expert witness to assist in the trial during the coroner’s inquest held a few months ago.