Plain-clothes detective with the Quetong police force, Lieutenant Sing was the one sent by Commissioner Wa to summon Dr. Quest and Race Bannon to his office. Later, it was revealed that Sing was a traitor who was working for General Fong, and he assisted Fong's soldiers in kidnapping Jonny and Hadji from their hotel room (unaware that a camera set up by the boys recorded his every move).
Pursued by Quest and Bannon in their helicopter, Sing crashed his car by driving it off a cliff, and was almost killed. Dr. Quest administered emergency medical attention to the detective, who relented and told him about General Fong's plans to launch a missile from Quetong. Regardless, Commissioner Wa revealed that Sing would be executed as a traitor, and it can be assumed that this sentence was eventually carried out.