An eight-year-old schoolgirl set off a massive police search yesterday when she went missing after crossing the border from Shenzhen at 9.30am. Mo Yau had returned from the mainland after spending the weekend with her mother in Shenzhen. She was scheduled to meet her father's domestic helper at Mongkok KCRC station at 10am, but failed to show up. Her father and the maid looked in KCRC stations but then reported her missing and a search was launched. About 2.5 hours later, the girl was found wandering in the arrival hall concourse at Lowu. After crossing the border, the girl had got lost and played on the concourse.