Offices of Malawi Congress Party (MCP) in Blantyre have been damaged following a petrol bomb attack.
The attack happened in the wee hours of Friday morning.
Fire-fighters were called to the scene of the incident but all property in the office had been damaged by the time they arrived.
On Thursday, Mia was at the High Court in Lilongwe where the Constitutional Court started hearing the presidential election case.
Last month, thugs also burnt down the Southern Region offices of the MCP.
The arson attacks are happening amid protests against the outcome of the May 21 presidential elections. The demonstrations are usually characterised by acts of lawlessness such as looting and burning of property.