THE mother of Elaine Luk Yee-ling, who was chloroformed and killed, has had to receive counselling several times since the 81/2-year jail sentence was passed on the killer last week. Family members, who will this morning petition the Attorney-General for a review of the sentence, said the 50-year-old mother, Wu Sau-yin, had been very depressed. ''My mother now looks like another person. In the past, she was talkative and positive about life, but now she's so quiet and upset that she seldom speaks,'' said Luk's 23-year-old sister, who declined to be named. ''We hope to get the sentence reviewed and make her feel more comfortable.'' She said the sentence was a blow to the family. ''We feel angry and depressed. We think it was unfair to Yee-ling. The killers should be given heavier sentences. ''We are under great pressure. Although we are all upset and do not want to think or talk about the tragedy again, we feel we have the responsibility to get the sentence reviewed. ''We have a responsibility to get justice done.'' Luk, 21, was lured to a hotel where she was chloroformed and videotaped while being sexually assaulted. Hon Leung-fong, her summer job employer, and his colleague, Phoebe Wong Yim-ping, were given 81/2 and seven years jail sentences respectively. Hon had received a total of 51/2 years' discount for his guilty plea, remorse and clear record. Luk's 55-year-old father, Luk Pak-luen, said Hon should be jailed for at least 15 years. He said his wife wanted Hon to be behind bars for at least 20 years. Mr Luk said: ''The sentence was absolutely unreasonable and unjust. How could he get a discount of 51/2 years?'' Solicitor Albert Ho Chun-yan, who is helping the family, said the reasons for the low sentence were weak and unjustified.