The South Korean spy agency's assertion that North Korea purged its defense chief and executed him with anti-aircraft fire is one of its boldest claims ever and, given the agency's checkered history, has come under growing scrutiny.
South Korea's National Intelligence Service (NIS) has a daunting major task — to look into archenemy North Korea, one of the world's most insular and hostile nations, and find out what is happening in its corridors of power.
The agency correctly revealed in 2013 that Jang Song Thaek, ruler Kim Jong Un's uncle and the second-most-powerful man in North Korea, had been purged.