Looks like Kim Jong Un’s executed uncle/deputy was trying to stage a coup and reform the country. From the write-up from KCNA, North Korea’s “news” agency:
As regards the means and methods for staging the coup, Jang said: “I was going to stage the coup by using army officers who had close ties with me or by mobilizing armed forces under the control of my confidants. I don’t know well about recently appointed army officers but have some acquaintances with those appointed in the past period.”
Jang dreamed such a foolish dream that once he seizes power by a base method, his despicable true colors as “reformist” known to the outside world would help his “new government” get “recognized” by foreign countries in a short span of time.
No matter how much water flows under the bridge and no matter how frequently a generation is replaced by new one, the lineage of Paektu will remain unchanged and irreplaceable.
Our party, state, army and people do not know anyone except Kim Il Sung, Kim Jong Il and Kim Jong Un.
Our service personnel and people will never pardon all those who dare disobey the unitary leadership of Kim Jong Un, challenge his absolute authority and oppose the lineage of Paektu to an individual but bring them to the stern court of history without fail and mercilessly punish them on behalf of the party and revolution, the country and its people, no matter where they are in hiding.