A Chilean judge on Friday formally accused six people of assassinating a former president in 1982, marking the second time in a decade he has moved to resolve the murder case.
Judge Alejandro Madrid charged doctor Patricio Silva, chauffeur Luis Becerra and intelligence agent Raul Lillo of poisoning Eduardo Frei Montalva,who governed Chile from 1964 to 1970, in a Santiago clinic in 1982.
Pedro Valdivia, another doctor, was accused of accessory to murder, while physicians Helmar Rosenberg and Sergio Gonzalez were accused of covering up the crime.
Court documents also showed that the assassination had been instigated by the right-wing dictatorship of Augusto Pinochet, Madrid said.
The judge had originally brought the charges against the six in 2009, but they were later dismissed.
However, an exhumation of Frei's remains ordered by Madrid last year revealed that the former president had been poisoned by "toxic substances" that were gradually introduced into his body. The findings strengthened the judge's case against the accused.
Lawyers representing the six men did comment on the charges.
"Today, we've learned of the judge's decision, and we're very moved," said Carmen Frei, daughter of Eduardo Frei. "All of this because my father had a conscience, because he acted firmly before the military dictatorship, because he had come to be a threat as he wanted to return to democracy."
Frei initially supported the coup that overthrew his leftist successor, Salvador Allende, and brought Pinochet to power in 1973. Frei’s support for Pinochet's regime quickly soured, and he subsequently became one of the most prominent figures in Chile's pro-democracy movement.
Since Pinochet's death in 2006, prosecutions of crimes committed during the dictatorship have picked up, as support for the former dictator, once strong in Chile's conservative circles, has begun to fade.
Pinochet himself never faced a full trial for human rights abuses committed under his rule, when more than 3,000 people were killed or disappeared and around 28,000 people were tortured.