Former Taiwanese president Chen Shui-bian, already sentenced to life in prison for corruption, could face treason charges after denying the legality of the government he once led. Justice Minister Wang Ching-feng said yesterday the Taiwan High Court would probe whether Chen was involved in treason or subversion aimed at overthrowing the island's government. Lu Hsueh-chang, secretary general of the ruling Kuomintang caucus, filed a lawsuit in the High Court against Chen for alleged treason. The trouble arose last month when, in a surprise move, Chen filed a lawsuit through a US lawyer against the White House claiming it failed to uphold US legal control over Taiwan and allowed the 'exiled government' to try him. Chen insisted that the US was Taiwan's 'principal occupying power'. He even claimed he had had to 'accept the instructions of the US on many occasions even when their instructions interfered with my presidential decision making'. Chen withdrew the lawsuit after it was rejected by a US military court.