A Chilean judge sentenced the country's former intelligence chief, retired Gen. Manuel Contreras, to two life prison terms Monday for masterminding a double assassination that was one of the most notorious covert operations conducted by this country's military government.

The historic court decision, which can be appealed, holds Contreras responsible for the murders of Gen. Carlos Prats, the former army chief, and his wife in a 1974 bombing attack in the Argentine capital of Buenos Aires.