SEOUL • In late 2013, Jang Song Thaek, an uncle of North Korean leader Kim Jong Un, was taken to the Gang Gun Military Academy in a Pyongyang suburb.
Hundreds of officials gathered there to witness the execution of two of Jang's trusted deputies from the administrative department of the ruling Workers' Party.
Ri Ryong Ha and Jang Su Gil were torn apart by anti-aircraft machine guns, according to South Korea's National Intelligence Service (NIS).
Jang - widely considered the second-most-powerful figure in the North - fainted during the ordeal, according to a new book published in South Korea that offers a rare glimpse into the secretive Pyongyang regime.
Written by Mr Ra Jong Yil, a former NIS deputy director, Son-In-Law Of A Theocracy is a rich biography of Mr Jang - the most prominent victim of the purges conducted by Mr Kim since he assumed power.
Jang was convicted of treason in 2013. He was executed at the same place and in the same way as his deputies, according to NIS.
The book asserts that, even though Jang was a fixture of the North Korean political elite for decades, he actually dreamed of reforming his country.
"With his execution, North Korea lost virtually the only person there who could have helped the country introduce reform and openness," Mr Ra said during a recent interview.
Mr Ra, who is also a professor of political science and previously served as South Korea's ambassador to Japan and Britain, mined existing publications but also interviewed sources in South Korea, Japan and China, including high-ranking defectors from the North who spoke on condition of anonymity.
After Mr Kim's father, former Korean leader Kim Jong Il, suffered a stroke in 2008 and died in 2011, Jang helped Mr Kim establish himself as successor.
At the same time, Jang vastly expanded his own influence - and ambitions. He wrested from the military the lucrative right of exporting coal to China and handed it to his own administrative department.
Mr Ra said it was impossible to establish the exact sequence of events that led to Jang's downfall. But it was clear that his hubris played a role.
At the height of his power, photographs published in North Korean media showed him leaning on an armrest, looking almost bored, while his nephew spoke.
In 2013, Mr Kim, after having heard complaints about Jang's expansion of power, ordered his department to relinquish the management of a fishing farm and a condensed milk factory. But officials loyal to Jang, their "Comrade No. 1", blocked those who arrived to carry out Mr Kim's orders from entering the premises.
It was probably the last straw for Mr Kim, who was still unsure about his position and extremely sensitive about any challenge to his supposedly monolithic leadership. Meanwhile, Jang's enemies in the secret police were eager to go after him.
"There was no indication that he had a lawyer or was allowed to speak for himself during his trial," Mr Ra said.
"It was not a trial but a murder."
NEW YORK TIMES