Vice-President Joyce Banda was sworn in as Malawi's new head of state on Saturday, the BBC reports. She is the first female head of state in southern Africa. President Bingu wa Mutharika went into cardiac arrest on Thursday, but his death wasn't officially announced until Saturday. Banda was one of President Mutharika's most vocal critics. She was expelled from the governing party in 2010 over her criticisms with Mutharika and went on to form her own opposition party. The delay in announcing his death was seen by some as the government trying to circumvent the constitution and install Mutharika's brother, Foreign Minister Peter Mutharika, as the new president. The Times says the President's party, the Democratic People's Party, did not see Banda as a legitimate successor because she had been expelled from their ranks.