Nigeria Union in South Africa has condemned the killing of a 34-year-old housewife, Mrs Christiana Onyeka, by unknown gunmen on December 3. Onyeka, a mother of four and native of Ozubulu, Ekwusigo Local Government Area of Anambra State, was killed in her husband`s office in Midrand, near Johannesburg. Mr Ikechukwu Ayene, president of the union, told…