Thirty years ago Jorge Julio Lopez was kidnapped and tortured under Argentina's dictatorship. Last month he vanished again at the end of a human rights trial in which he was a key witness, and the government's efforts to find him have turned up little.

Lopez testified in the case against former police commissioner Miguel Etchecolatz, who was sentenced to life in prison in September for crimes committed during Argentina's 1976-1983 "dirty war."

His disappearance has stirred up memories of the dictatorship, leading to fears for other witnesses' safety, and the nationwide search for the 77-year-old mason has degenerated into political finger-pointing.