The recent execution of North Korean Defense Minister Hyon Yong-chol is a sign that Kim Jong Un is not feeling very confident as that nation's leader, according to expert Michael Madden.

While the exact reason for Hyon's death is not entirely clear, whether it was the result of "emotional security" because of a personal issue Kim Jong Un had with Hyon, "the insecurity he feels discharging the job of North Korean leader," or some kind of "power play," either way "this is not the sign of a man confident in his job," Madden writes for BBC News.

Hyon, 66, was allegedly executed on treason charges for several reasons, including falling asleep at a recent event attended by Kim Jong Un. He was executed in public by anti-aircraft gunfire.

Madden says that "there is little in Hyon Yong-chol's profile that tells us why Kim Jong Un may have wanted to eliminate him."

He explains the Hyon was someone who was very familiar with North Korea's military situation, including the nation's weapons programs.

Hyon was the fourth defense minister in North Korea since April 2012, which Madden says suggests a "persistent risk of instability."

The North Korea expert says that he has heard from his own sources that Hyon is not the only one who was executed.

"We know about the report from NK News about images — which could not be confirmed — showing large weaponry facing a very close target, a viewing area and several passenger vehicles," he writes.

"They believe it could be a 'gruesome public execution' by anti-aircraft fire, the way that Mr. Hyon appears to have gone," Madden added.

North Korea reportedly executed 15 senior officials, who allegedly complained with Kim Jong Un about his policies in April as well as four members of an orchestra.

Kim Jong Un also reportedly executed his own uncle, Jang Song-taek, in December 2013. Jang's execution was followed by a purge of his family. 

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