STEPHEN Tse Kwok-yau blinked back tears last night as he remembered his studious, piano-playing daughter now languishing in a Bangkok jail. ''I miss her. I miss her in my heart,'' said Mr Tse at the comfortable Mei Foo Sun Chuen home he shares with his mother, brother, sister-in-law and two sons. ''She was not guilty. She would not have done something like this. She was so young.'' As he flicked through photographs of the plump, tall, bespectacled, clean-living girl, he recalled how Michelle had set her heart on studying at law school in Canada. She had gone to Thailand with a friend for a holiday after graduating from Tak Ching Catholic School for Girls. She was accompanied by a classmate, who had been expelled from the school just before graduation. The friend, whom police believe now lives in Macau, introduced Michelle to a Thai acquaintance on the plane. Once in Bangkok, the Thai man introduced them to a friend of his, who became their tour guide. ''Michelle told us that when she was stopped at customs this man's jacket was in her suitcase. It had drugs in it. She didn't know how it got there. ''In Thailand, the law says if you can't prove you don't know how drugs got in your possession then you are guilty. That's not fair,'' said Mr Tse, a manager for a clothing firm. Michelle was found guilty and sentenced to 121/2 years' jail. Mr Tse's passport is filled with immigration stamps for Thailand, testimony to the numerous trips he has made to see his beloved daughter. He has long been separated from his wife, who now lives in Canada. He takes her cash, shampoo, food and perfume. ''She can buy favours with these things. We worry that she doesn't get enough to eat,'' he said. ''She is very unhappy and lonely. She was very sad when her grandmother went into hospital for an operation on a cancer. She wanted to see her.'' If nothing else works, he hopes Michelle will become eligible for transfer to a Hong Kong prison under a prisoner exchange agreement between the two countries. ''At least then she will be nearer. We will be able to see her more often.''