Dr Aribert Heim
Heim, who ranks alongside Mengele as one of the most reviled Nazis, was thought to have died until, in 2005, bank documents suggested he was alive, possibly in Chile. Heim, 94, murdered hundreds of Jews at Mauthausen concentration camp in 1941by subjecting them to his "experiments" .
Sudan's President came to power in an Islamist-backed coup in 1989. This month, the prosecutor of the International Criminal Court accused Al-Bashir, 64, of genocide, crimes against humanity and war crimes in Darfur, where more than 250,000 people have died since 2003.
Karadzic's right-hand man, Ratko Mladic was the Bosnian Serb military commander. Mladic, 65, is accused of conspiring to massacre 7,500 men and boys in Srebrenica in 1995. The pair are also indicted for the siege of Sarajevo, which left 10,000 dead. Mladic has been in hiding since 2001.
As leader of Uganda's notorious rebel Lord's Resistance Army (LRA), Kony, 46, has been called bandit, terrorist, prophet and madman. He wants to rule according to the Ten Commandments, yet the LRA has abducted girls to be sex slaves and boys killers. Wanted for crimes against humanity.
The ICC issued an arrest warrant in 2006 for Congolese warlord Ntaganda. As a leader in the rebel Patriotic Forces for the Liberation of the Congo (FPLC), Ntaganda, 35, is accused of conscripting child soldiers and taking part in FPLC attacks in which an estimated 50,000 people were killed.
...and five facing trial
Lubanga, 47, who led a militia in the Democratic Republic of Congo, was arrested in 2005 following the murder of nine UN peacekeepers, and again on a charge of enlisting children. He has been on trial at The Hague but could walk free, over the prosecution's stance on witnesses.
Mengistu Haile Mariam
When the former Ethiopian president fled his country in 1991, he left a land ravaged by famine. Mengistu, now 71, is held responsible for the deaths of thousands of Ethiopians during the 1970s. This year, he was sentenced to death in absentia in Ethiopia but remains exiled in Zimbabwe.
Taylor, 60, started Liberia's civil war as a warlord in 1989, before being elected president in 1997. He faces charges of war crimes and crimes against humanity for his alleged role in the civil war in neighbouring Sierra Leone. His presidency ended in 2003 and he is on trial in The Hague.
Kaing Guek Eav ('Duch')
The former head of interrogations at Phnom Penh's notorious Tuol Sleng jail is one of five former Khmer Rouge figures still on trial in Cambodia. Pol Pot's regime is blamed for the deaths of 1.7 million people. Pot died in 1998 and the remaining targets are becoming increasingly frail.
The magnate and former Democratic Republic of Congo warlord was arrested near Brussels this year. Bemba, who is about 45, is charged with crimes against humanity and war crimes as head of a militia that allegedly committed atrocities in the Central African Republic in 2002-03.