Between 1976 and 1985 the military dictators of Argentina operated a policy of kidnapping, torturing, murdering and "disappearing" their political opponents. Children of their victims were often adopted, sometimes by the very people who had tortured and murdered their parents. (Fascist Spain operated a similar programme of forced adoptions during and after the Civil War, and the German Democratic Republic also operated such a policy of forcible adoption of dissidents' children.)
There is a campaign now, Grandmothers of the Plaza de Mayo, run by the parents of the dead and missing, to find and reclaim their grandchildren. Of an estimated 200 such orphans, about 55 have been traced and 30 of them have been reunited with their biological families.
A different policy was operated in El Salvador during the civil war in the 1980s. Government troops kidnapped and stole thousands of children in insurgent areas and placed them for adoption within El Salvador and overseas, pretending they were orphans, and pocketing large sums of money in fees and bribes. An organization, The Association in Search of Disappeared Children, has been successful in reuniting some of the children with their birth families.