This New York Times article reveals S. Korea's dark past. During the military dictatorships in the 1960s to the 1980s, some South Koreans were persecuted under the name of political subversion. At the end of 2005, the government of President Roh Moo-hyun established Truth and Reconciliation Commission to investigate those cases, and verdicts are being reviewed and some cases were overturned.
This should be a good thing as the government is seeking justice for those who were wronged. But Park Geun-hye, the daughter of Park Chung-hee, who ruled South Korea with an iron fist for 18 years until his assassination in 1979, told reporters in January that, "this is a political offensive against me." -- An interesting twist in the story.