'I don't know how he could support himself. He might have been picking up rubbish to feed himself'

The distraught mother of missing mentally disabled boy Yu Man-hon last night told how she was trying to overcome the pain of separation from the son she spent so much effort bringing up.

Speaking from Shenzhen, where she has spent several days looking for him, Yu Lai Wai-ling said she found it hard to accept when she first learned Man-hon, 15, was autistic. 'But he was my son and I am obliged to love him.'

Man-hon was diagnosed with autism when he was two years old after Mrs Yu found he was unable to speak and seemed over-active.

'I brought him to see a lot of doctors and enrolled him in lots of training. But he was more or less the same as before after years of training,' she said.

Man-hon had been very violent at home. He used to tear up his shirts, he broke the TV set, overturned the dining table and threw things out of the window.

'He ate a lot and was very strong, especially when he lost his temper. But from the bottom of his heart, he was very pure,' she said.