The International Criminal Court has dropped all charges against Kenya's former head of the civil service accused alongside president-elect Uhuru Kenyatta of crimes against humanity during the 2007-2008 post-election violence.
The decision to drop charges against Francis Muthaura was announced on Monday by the court's chief prosecutor, Fatou Bensouda, at The Hague in the Netherlands.
Bensouda said the charges were dropped after a key witness in Muthaura's case was discredited.
The witness confessed that he had "accepted bribes", Bensouda said.
The prosecutor also said other witnesses against Muthaura refused to testify or had died.
"I have decided, as of the state of evidence available now, that we have no other choice but to withdraw the charges against Mr Muthaura," Bensouda told court.
But Bensouda said charges against Kenyatta, who was elected president in the March 4 general election, and William Ruto, his running mate, would not be dropped.
"This decision applies only to Mr Muthaura. It does not apply to any other case," she said.
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"While we are all aware of political developments in Kenya, these have no influence, at all, on the decisions that I make as prosecutor of the International Criminal Court."
Kenyatta, Ruto and four other Kenyans were singled out by the court in 2010 for their alleged involvement in fomenting the post-election violence of 2007-2008 in which 1,200 people were killed.
But the court has narrowed its attention on Ruto, Kenyatta and radio presenter Joshua Sang. The trial of Ruto and Kenyatta is due to begin in May and July 2013 respectively.
The Kenyan opposition disputed the outcome of a presidential vote, unleashing the worst unrest in the east African country since independence in 1963.
More than 663,000 people were displaced in Kenya's Rift Valley after fights between rival supporters, prosecutors said, when politically motivated riots soon turned into ethnic killings, which in turn sparked further reprisals.