A MOTHER who throttled her baby daughter to death because the child would not stop crying was yesterday sent to a mental hospital. Chau Fung-chu, 28, killed 10-month-old Mei-ki in a fit of temper when the baby awoke screaming. But the mother, who accused her husband of killing their baby, was suffering from severe post-natal depression which had altered her mental state, the High Court heard. Chau, who sent Mei-ki to relatives in China after the birth, killed her daughter two weeks after she returned to her parents in Tuen Mun. Days before Mei-ki's death, her mother complained of hearing voices telling her to strangle her child. When doctors examined Mei-ki's body they discovered 30 injuries, many of them several days old, prosecutor Stephen Wong said. Mr Justice Stuart-Moore ordered Chau be detained for six months under the Mental Health Ordinance at the Siu Lam Psychiatric Centre. He told Chau: ''This is beyond question a dreadfully sad case where I am satisfied that punishment in the ordinary sense is simply not appropriate. ''You have never really come to terms with the enormity of what you have done. Your actions in killing your daughter were the product of an unbalanced mind.'' Psychiatrist Dr Michael Yiu said Chau's condition could be treated but she was still suffering from a depressive illness and was at risk of committing suicide. The jury heard Mei-ki woke up crying on January 30 last year. To stop her yelling Chau smothered the girl with a blanket. She then gripped her daughter's neck, pressing on her throat for up to three minutes. Chau tried to commit suicide after she was admitted to the Castle Peak Hospital.