By Tom Gibb
BBC South America correspondent
Divers in Chile have recovered pieces of railway alleged to have been used to sink the bodies of government opponents murdered during the Pinochet regime.
More than 3,000 dissidents were killed under Pinochet
The search was ordered by a judge who is investigating the disappearance and murder of left-wing sympathisers.
More than 3,000 people are believed to have been killed by the police and military under Gen Augusto Pinochet.
The pieces of rail track found off Chile's coastline add evidence to testimonies given by ex-army officers.
'No human remains'
They say some of those tortured and killed when Gen Pinochet seized power in 1973 were first buried in a mass grave, but then the bodies were dug up and dumped at sea, so as to hide the evidence.
Judge Juan Guzman watched as the rusty pieces of railway line were hauled to the surface.
No human remains or ropes were found.
This is just one of several cases against Chile's 88-year-old former ruler which the judge is investigating.
Last month, a Supreme Court ruling opened the way for Gen Pinochet to stand trial in another case in which 19 government opponents were allegedly killed as part of Operation Condor.
This is where South America's military rulers shared intelligence about suspected Communists.
Gen Pinochet not been brought to trial in any of the cases. His defence team has consistently argued that he is mentally unfit to stand trial.