(left) President Kim Jong-un, (right) murdered victim Kim Jong-nam
Najib believes the North Korean ambassador has been rude, and dear Hisham thinks the bloke from Pyongyang has crossed the line, wakakaka. Our ministers might not know what North Koreans, ambassadors or not, could be capable of, that is, if they (the North Korean embassy staff) value their own lives from their own country.
On 9 October 1983, North Korean agents bombed Rangoon (now Yangoon) in an attempt to murder visiting South Korean President Chun Doo-hwan, the 5th President of South Korea - read this for more details.
From Wikipedia: Chun was sentenced to death in 1996 for his role in the Gwangju Massacre, but later pardoned by President Kim Young-sam with the advice of then President-elect Kim Dae-jung, whom Chun's administration had sentenced to death some 20 years earlier.
In November 2009, Swedish police arrested two North Korean embassy staff for smuggling 230,000 Russian cigarettes into Sweden.
Much earlier, in 1978, North Korean agents kidnapped a top actress from South Korea (Choi Eun-hee, Korea’s most famous actress) and subsequently, also kidnapped her husband, famed Korean film director Shin Sang-ok. The former (late) President Kim Jong-il wanted them to make propaganda films for him.
the kidnapped couple subsequently escaped in Vienna in 1986
North Koreans had also kidnapped others, mainly Japanese, to train North Koreans as spies and also to provide Japanese identities for North Korean spies.