Ethiopia's most senior judge, Teshale Aberra, has left the country following threats and "continued harassment" from the government, he has told the BBC.
The Supreme Court president accused the government of Prime Minister Meles Zenawi of killing its critics but managing to avoid international blame.
He also said the government was planning to appoint new, loyalist judges throughout the system.
Mr Meles had been seen as being part of a new generation of African leaders.
Mr Teshale is the latest in a series of senior officials - judges, diplomats and military commanders - to flee the country.
He told the BBC's Focus on Africa programme that Mr Meles' government was just as bad as that of its predecessor, led by Mengistu Haile Mariam, who is accused of crimes against humanity.
"The difference is these guys as wise... These people kill whoever they feel like and then ask: 'Who killed them?'"
Students accused the police of brutality during protests last year
Another judge, Wolde-Michael Meshesha, recently fled the country after carrying out an investigation into the suppression of protests against alleged fraud in last year's elections.
In his report, he said the police had massacred 193 people.
His report said that the government had concealed the true extent of deaths at the hands of the police.
He claimed he had been put under pressure to alter his findings and fled into hiding in Europe when he received anonymous death threats.
More than 100 opposition leaders, journalists and aid workers were rounded up during the protests and are currently on trial, accused of treason and attempted genocide.
Police records showed 20,000 people were arrested during the anti-government protests, the judge said.
In January, Britain withheld $87m in aid because of concerns over the unrest.
Last year, Mr Meles was invited onto the panel of the UK's Commission for Africa to find ways of relieving poverty in the world poorest continent.