SOUTH African investigators raided the home of National Assembly speaker Nosiviwe Mapisa-Nqakula as part of a corruption inquiry against her, the parliament said. The operation by the National Prosecution Authority (NPA) Investigating Directorate was linked to a probe into alleged corruption during the speaker's time as defence minister, parliament said in a statement. South Africa's state-owned broadcaster SABC reported that Mapisa-Nqakula, who lives in Johannesburg, is suspected of receiving millions of rands in cash as bribes from a former military contractor when she was defence minister. "The Speaker steadfastly upholds her strong conviction of innocence, and reaffirms that she has…