I'm not personally aware of any. However, you can understand that a lot of the threats North Koreans feel when resettling in South Korea result from the proximity to North Korea and how North Korean agents might be able to more easily infiltrate in a country like South Korea, given the cultural and language similarities. What a lot of the North Koreans feel is just that anxiety of being identified. It's just as much a risk in terms of spies as it is for them in being identified on the street anywhere.
On October 2nd, 2014. See this statement in context.