A judge in Chile has ordered the arrest of eight former police and army officials over the kidnapping of a US hiker during the Pinochet years.
Boris Weisfeiler, a Princeton University mathematics professor, disappeared in 1985 while hiking on his own near Chile's border with Argentina.
Judge Jorge Zepeda cited evidence from declassified US files.
This includes witness accounts of how Mr Weisfeiler was abducted and brought to a secret police torture centre.
The centre was located in Colonia Dignidad, a former German enclave founded in the 1960s by a former Nazi nurse, near the city of Parral, some 350km (220 miles) south of the capital, Santiago.
The suspects will be tried for "aggravated kidnapping" and "complicity" over the American's disappearance, judicial authorities said in a statement.
'Tortured and executed'
Mr Weisfeiler, who was born in Moscow in 1941 and naturalised as a US citizen in 1981, had been visiting Chile alone during his winter holiday when he vanished.
It is believed he was walking near the border with Argentina when the suspects allegedly seized him because he was wearing military garb, leading them believe he was a militant.
The suspects have until today "persistently tried to conceal information about the circumstances of the arrest and whereabouts of the American citizen", the judicial authorities' statement said.
Initial Chilean police reports said Mr Weisfeiler, an experienced hiker, had drowned while trying to cross a river and his body had not been recovered.
However, declassified US embassy cables on the case suggested he had been arrested by either the police or an army patrol and taken to Colonia Dignidad.
An informant claiming to have been a member of the military patrol that arrested him said he had been interrogated, tortured and finally executed at the colony, journalist Mary Helen Spooner wrote in a blog post for University of California Press last year.
Mr Weisfeiler's sister Olga has been searching for answers about his fate since his disappearance, and has retraced her brother's route along the river where police said they had found his backpack.
"It has been a very challenging 27 years for me and my family since Boris disappeared," she told the BBC News website in an email on Wednesday.
"The indictments are long awaited and extremely welcome news. However, this is only the first step of a long process of accounting for Boris' fate, that will hopefully bring resolution to the case so that we may know what happened to my brother."
In Chile, some 350 cases remain open involving about 700 military officers and civilians active under the late Gen Augusto Pinochet's rule (1973-1990), AFP news agency reports.
Some 3,000 people disappeared or were killed during that time.
Colonia Dignidad was founded in a valley in the Andean foothills in the early 1960s and grew to number about 300 members.
It was created by the late Paul Schaefer, a former Nazi who had fled child abuse allegations in Germany.
The 137-sq-km (53-sq-mile) project reportedly made millions of dollars through businesses which included agriculture, mining and real estate.
Thanks to Schaefer's close links with Chile's ruling elite, the colony was able to operate with impunity as a "state within a state", a Chilean congressional report found.
After the Chilean authorities investigated Colonia Dignidad in 2005, former members of the colony issued a public apology for child abuse, and human rights abuses, stretching back decades.
Schaefer died in 2010 while serving a prison sentence for child abuse and other crimes.