The apparent assassination in Malaysia of North Korean leader Kim Jong-un’s half-brother has intelligence agents, North Korea watchers and the media scurrying to find the motives behind the high-profile incident.

One group points to the possibility that the North Korean leader ordered the killing of Kim Jong-nam in order to remove any potential threat to his power.

Those who belong to the group say that Kim Jong-un wanted to get rid of his brother because Kim Jong-nam, being a key member of the Kim clan who ruled the country since 1945, could be viewed as an alternative leader if Kim Jong-un loses control of the country.

Closely related to this argument is the view that China had long been protective of Kim Jong-nam, who often stayed in Macau, a Chinese territory, partly because it thought of him as a substitute for Kim Jong-un should the regime fall.

They note that there has been persistent talk of a possible regime change or brewing discontent in the North lately. Thae Yong-ho, a former senior diplomat in the North Korean Embassy in London, said recently that many senior government officials are fed up with the repressive rule of the 34-year-old dictator.

Since the inauguration of Donald Trump as US president, more officials and legislators in Washington also talk about the need to seek a regime change to thwart the North’s nuclear and missile ambitions.

There were also unconfirmed reports that Kim Jong-nam, who had been in exile in recent years, sought to seek asylum and that he did not comply with his brother’s order to return home.

While those reports have yet to be verified, Kim Jong-nam -- speaking to journalists on two occasions years ago -- expressed critical views of the dynastic inheritance of power in the North. Kim Jong-nam’s son, Han-sol, once said he did not know how Kim Jong-un became a “dictator.”

Whatever motive the North Korean leader may have had, what seems to be certain is that Kim Jong-un had been determined to get rid of his brother. Lee Byung-ho, the chief of South Korea’s National Intelligence Service, told lawmakers that the North had had a “standing order” to kill Kim Jong-nam since 2012, when there was an attempt on his life.

That offers a clear demonstration of the ruthlessness of the Kim family, which has ruled the communist country with a merciless ax that does not spare family members or close associates.

The killing of Kim Jong-nam reminds many South Koreans of the murder of Lee Han-young, a nephew of Kim Jong-nam’s mother in 1997. Lee, who defected to South Korea in 1985, was shot by gunmen believed to have been sent by the North.

Kim Jong-un is no less brutal than his father and grandfather, as evidenced by the shocking execution of his uncle Jang Song-thaek who had been regarded as the No. 2 man in the power hierarchy, in 2013. That was two years after Kim took power upon the death of his father, and Jang’s execution was largely seen as a move to thwart any challenges to his leadership by fortifying his reign of terror.

Kim is believed to have executed about 140 members of the country’s ruling elite, including relatives and former key aides to his father, since he took power in 2011. All those cases are related to Kim’s efforts to magnify fear of his rule and force submission.

North Korea watchers say the past cases and the killing of Kim Jong-nam indicate that Kim Jong-un is as unpredictable and ruthless as his father and grandfather. Lee of the NIS said that the latest assassination shows that Kim is captivated by a sense of paranoia.

This means that a young paranoiac man who is so inhumane, ruthless and brutal has in his hands what is believed to be in the final stage of deliverable nuclear bombs.

Kim Jong-nam’s assassination came one day after North Korea test-fired a new intermediate-range ballistic missile, the first such provocation since the start of the Trump administration in the US.

Lee of the NIS, noting that the North had been trying to kill Kim Jong-nam for five years, said that the two events are not related. But these latest developments oblige us to keep closer tabs on the North.