The stand-off caps a week of diplomatic drama.
On March 6th Malaysia kicked out the North Korean ambassador, Kang Chol, who denies that North Korean spies were responsible for the murder or that the victim was Kim Jong Nam; he accused Malaysia of cooking up the story with America and South Korea to blacken the North's reputation.
The North Korean government formally expelled Malaysia's ambassador the same day, though by then his bosses had already called him back to Kuala Lumpur.
In a further display of recalcitrance, North Korea tested four missiles simultaneously on March 6th, in defiance of UN sanctions.
In response to the North's frequent tests, America and South Korea are accelerating the deployment in South Korea of THAAD, an American anti-missile system.
That, in turn, has riled China, which fears THAAD could render its missiles less potent, too.
Meanwhile, on March 8th, a previously unknown outfit called Cheollima Civil Defence posted a video it said was of Kim Han Sol, the son of Kim Jong Nam.
It claimed to have responded to a request to “extract and protect” him from his home in Macau, along with his mother and sister.
The group said it had received help from China, America and the Netherlands.
Whether Kim Han Sol will become a vocal critic of the regime that murdered his father, or choose to vanish from sight, remains unclear.