Gen Ratko Mladic (69) was the military leader of the Bosnian Serbs during the country's 1992-1995 war, and was seen as Radovan Karadzic's right-hand man, realising on the ground his boss's vision of an ethnically pure "Greater Serbia".
Like Karadzic, Mladic was indicted by the UN war crimes court for committing genocide during the 43-month siege of Sarajevo, which killed some 12,000 people, and for the July 1995 Srebrenica massacre of 8,000 Muslim men and boys.
He is also accused of killing and deporting non-Serbs during "ethnic cleansing" campaigns in Bosnia in 1992 and 1993, and of bearing responsibility for the use of torture and sexual violence against Bosnian Muslims in deadly attacks which the UN court alleges were intended to achieve "the physical destruction of Bosnian Muslims".
Mladic received pay from the Serb military for several years after his indictment, and is thought to have be hiding in Serbia with the help of elements of the security services.