Kim Hong-Ji / Reuters
Citing accounts pieced together by American and South Korean officials, Jang Song-thaek, along with loyalists, reportedly seized crab and clam-rich fishing grounds from the military in an effort to dominate lucrative business deals with China.
From The New York Times:
The rout of his forces appears to have been the final straw for Mr. Kim, who saw his 67-year-old uncle as a threat to his authority over the military and, just as important, to his own family's dwindling sources of revenue. Eventually, at Mr. Kim's order, the North Korean military came back with a larger force and prevailed. Soon, Mr. Jang's two top lieutenants were executed.
The two men died in front of a firing squad. But instead of rifles, the squad used antiaircraft machine guns, a form of execution that according to South Korean intelligence officials and news media was similar to the one used against some North Korean artists in August. Days later, Mr. Jang himself was publicly denounced, tried and executed, by more traditional means.
The report from The Times somewhat explains the strongly-worded news release from North Korea's state-owned news agency of Jang's arrest and subsequent execution.
He was literally erased from photographs, and called "despicable human scum ... worse than a dog" who perpetrated "acts of treachery in betrayal of such profound trust and warmest paternal love shown by the party and the leader for him."
He was widely considered one of the most powerful people in North Korea, helping the young Kim learn the ropes after the death of his father Kim Jong-il in 2011. Jang's wife, Kim Kyong Hui, still remains part of Kim Jong-un's inner circle, according to Reuters.