North Korea defence chief
Senior North Korean military officer Hyon Yong Chol delivers a speech during the 4th Moscow Conference on International Security (MCIS) in Moscow April 16, 2015.Reuters

After reports of yet another public execution in North Korea at the behest of its supreme leader Kim Jong-un went viral, doubts have emerged whether the country's defence chief was actually killed by an anti-aircraft gun for 'falling asleep' at a meeting. 

South Korea's National Intelligence Service had claimed on Wednesday that Hyon Yong Chol, 66, who was only recently seen giving a speech in Moscow last  month, was executed on 30 April. 

The reasons cited were that Hyon showed disrespect to Kim Jong-un and fell asleep in his presence at a meeting, justifications common in executions by the whimsical leader. 

However, analysts view this claim with scepticism, especially since the North Korean defence chief 'appeared' on television this week in a propaganda film alongside Kim.  

This public appearance in the propaganda film, which may be old, casts doubt on the claims of Hyon's execution, as in the past, North Korea has been careful to remove all images of those executed, from public domain.  

"We've seen Hyun even yesterday on TV. If North Korea really executed their number-two man in charge of defense, they would make sure he disappears on every single program. That's definitely their style," Shin Kyoung-min, a South Korean assembly man, told ABC News on Wednesday. 

The report said that the South Korean agency had also made two different statements to the national assembly and to the press. 

While the NIS was confident in its claim to the assembly that Hyon was executed in public by an anti-aircraft gun on 30 April, it released a more watered-down statement to the press. 

"We confirm that Hyon Yong-chol was purged [not executed]. We do have intelligence information that he had been killed by gunfire but that is yet to be verified," a NIS official told the channel. 

South Korean officials themselves expressed surprise that the 'executed' defence minister was still appearing on TV. 

"There needs to be more analysis on why Hyon is still appearing in the TV footage," an official with S Korea's Ministry of Unification said on Thursday, Yonhap news agency reported. 

Adding to speculations is the South Korean agency's track record of making erronous announcements of events happening in the North. 

However, because the Kim Jong-un regime keeps its affairs secret from the world, it may be a while before the air on the execution is cleared.