Uruguay's Supreme Court says an amnesty given for any crimes committed by the country's 12-year dictatorship is unconstitutional.
A court spokesman says the ruling means about 20 murders in a case against former dictator Juan Maria Bordaberry can be investigated.
Uruguay's dictatorship ruled until 1985, followed by an amnesty that covered both sides _ dictatorship figures and leftist guerrillas. The amnesty was twice upheld by voters in national referendums.
Bordaberry, now in his 80s, is one of very few Uruguayans to face trial anyway. He was sentenced to 30 years in prison in February for violating the constitution when he led the 1973 coup. He has been serving the sentence at home due to his age and ill health.