A mentally ill mother, who was left to care for her three children after a divorce, is suing Citic Ka Wah Bank to recover her HK$6 million minibond investment which, she says, is all of her savings. Yesterday, the younger sister of Lau Wai-lan filed a writ in the High Court with the help of Democratic Party lawmaker Albert Ho Chun-yan. Speaking on her sister's behalf, Lau Wai-ping criticised the bank, saying it had ignored requests for talks on compensation for the HK$6 million loss following the collapse of Lehman Brothers. Some 48,000 Hongkongers bought about HK$20 billion worth of Lehman-linked derivatives. Most bought minibonds - which are not corporate bonds, but high-risk, credit-linked derivatives. They are sold as proxy investments in well-known firms. Lau Wai-ping alleged that her sister was misled by the bank into taking the HK$6 million out of a fixeddeposit account and investing it in minibonds. Her sister's mental condition had deteriorated since she learned of the loss, she added. 'This is not only about money ... it concerns four people's lives,' Ms Lau said. Mr Ho said that Lau Wai-lan, 46, had been granted custody of the children, now aged from eight to 15, after the divorce. Her former husband had given her a flat as part of the divorce settlement. As she was unable to work due to mental illness, Lau Wai-lan sold the flat in 2005 for about HK$6.2 million and used the interest earned from the deposits to support the family. In January 2006, she deposited HK$3 million in a fixed-deposit account at the Tai Wai Branch of the bank. She was later persuaded by a bank manager to invest in minibond products. In August 2006, the same manager persuaded her to invest another HK$3 million in another series of minibonds. The writ alleges that the manager made false and misleading representations and that Lau Wai-lan was never told the investment products were high-risk. Meanwhile, a housewife is seeking HK$120,000 from DBS bank for her minibond losses. In a writ filed in the District Court yesterday, Lai Yuet-wan, 56, alleged she was misled into investing by bank staff in June 2006.