It is believed that factions within the ruling ANC party spied on each other during those tense times.
Mandela's grandson, Mandla Mandela, who is a member of parliament, said he could not comment because he had no knowledge of the matter.
Brian Sokutu, an ANC spokesman, also claimed ignorance but said that the ANC would be alarmed if an invasion of anyone's home took place, "particularly the house of a leader".
Vavi presented the results of high-level Cosatu deliberations on Thursday and concluded: "We are headed in the direction of a full-blown predator state, in which a powerful, corrupt and demagogic elite of political hyenas increasingly controls the state ...''
He said that ANC politicians in upcoming local elections could not expect Cosatu's support if they were corrupt or unproductive.
Meanwhile, the union confederation has split with the ANC on economic matters, supporting a nationwide public service strike that entered its second week on Thursday.
Civil servants are demanding an 8.6 per cent pay raise and a 1,000 rand ($137) housing allowance.
The government is offering a seven per cent wage increase plus 700 rand ($96) for housing, and says it cannot afford any more.