North Korea claimed that they arrested a terrorist that received orders from South Korea and the US government to infiltrate North Korea.
In addition, they warned that regardless of position, status, anybody who dares to lay a finger or insults on the highest dignity (Kim Il-Sung·Kim Jong-Il·Kim Jong-Un) will face severe punishment.
According to a North Korean defector organization in Korea the ex-North Korean People's Army personnel defectors planned infiltrated into North Korea to demolish Kim family related statues and monument memorials. I am guessing that the terrorists are the ex-army defectors.
North Korea is exaggerating the infiltrators as a terrorist who took order from the Korean, and US government.
As internal discord that makes Kim Jong-Un's power in North Korea precarious, they are resorting to the expedient measures to pass on the responsibility and make the Korea and the US government a scapegoat. Their efforts are pitiful.