Kim Jong Nam's assassination in the Malaysian capital on February 13 has snowballed into a major diplomatic spat between Kuala Lumpur and Pyongyang.

Malaysian authorities investigating the crime on Wednesday sought permission to question a high-ranking official of the North Korean embassy in Kuala Lumpur, Second Secretary Hyon Kwang Song, in connection with the incident. They also added a North Korean airline employee to the list of suspects.

"We have written to the ambassador to allow us to interview both of them. We hope that the Korean embassy will cooperate with us and allow us to interview them quickly. If not, we will compel them to come to us," Malaysia's top policeman Khalid Abu Bakar told reporters.

Kim appeared to have been poisoned at Kuala Lumpur's international airport and leaked CCTV footage from the airport shows the 45-year-old being approached by two women, one of whom grabs him from behind and appears to shove a cloth in his face.

Malaysian police say he suffered a seizure and died before he reached the hospital, seemingly from the effects of a toxin. They have so far arrested four people, including the two women who were allegedly seen approaching Kim.

South Korea has blamed Pyongyang for the murder, citing a "standing order" from North Korean ruler Kim Jong Un to kill his elder half-brother, and a failed assassination bid in 2012.

'Downgrade inevitable'

Whereas Pyongyang has so far maintained a studied silence over Kim's killing, there has been an acrimonious exchange of words between North Korea's ambassador to Kuala Lumpur, Kang Chol, and Malaysian officials.

Days after the killing, Kang castigated Malaysia's handling of the incident, accusing Kuala Lumpur of "colluding" with South Korea to frame the North.

That prompted a rebuke from Malaysian Prime Minister Najib Razak, who criticized the envoy as being "diplomatically rude" for making statements that were "totally uncalled for." Kuala Lumpur has also recalled its ambassador to Pyongyang.

Observers say the remarks made by the North Korean ambassador are forcing the Malaysian police and foreign ministry to respond firmly.

"The trouble is that the North Korean ambassador needs to keep making these unhinged statements - that's the only way that's acceptable to his superiors in Pyongyang," said Shahriman Lockman, a senior analyst at the Institute of Strategic and International Studies Malaysia (ISIS), a think tank. 

"While I certainly don't expect the relationship to be severed, a form of downgrade looks inevitable at this stage," he added.

Close ties

Such deterioration would be a major setback for North Korea. That's because since Malaysia established diplomatic ties with North Korea in 1973, Kuala Lumpur has maintained a close partnership with the reclusive regime in Pyongyang.

Malaysia's importance in the international community's dealings with Pyongyang can be observed in the fact that it often discreetly hosts diplomatic talks between US and North Korean officials on the regime's controversial nuclear program.

The two nations also accord reciprocal visa-free travel to each other's citizens, and a small community of North Korean expats in Malaysia is said to be engaged in business and money-making schemes for the Pyongyang regime hit hard by crippling UN sanctions.  

"The relationship gave the North Koreans a modicum of diplomatic space and a place where they can gain some foreign currency," Lockman told DW. 

"Nonetheless, most Malaysians are surprised that there's even a North Korean embassy in Kuala Lumpur. The North Koreans certainly need us more than we would ever need them," he stressed, pointing out that annual trade between the two sides account for a mere 0.002 percent of Malaysia's total external commerce.

What next?

But what measures can Malaysia take in case North Korea refused to cooperate with the authorities investigating Kim's murder there?

The chances of Malaysian police questioning embassy official Hyon Kwang Song appear almost nil as he enjoys diplomatic immunity, say experts. 

Furthermore, Lockman underlines, if the Air Koryo employee is inside the embassy now, the police would have difficulties questioning him as diplomatic premises are inviolable under the Vienna Convention. "I would be surprised if the police would ever get to talk to these individuals," he noted.

Zachary Abuza, a Southeast Asia security expert and professor at the Washington-based National War College, said Malaysian leverage in this instance is economic.

"I have no doubt that North Korea uses the Malaysian banking sector as one of its few international financial gateways for settling trade," he told DW, adding that it is also a key source of electronics and other goods that the Pyongyang regime imports. "While the overall trade levels are paltry, especially for Malaysia, they are important for North Korea."

In this context, the analyst points out that Malaysia could start to investigate North Korean businesses for financial improprieties, or limit the number of Koreans who have residence cards. "They could also abrogate their agreement on visa-free travel."

At this stage, most Malaysians are just astounded, says analyst Lockman. "But that initial shock is now gradually turning into anger after the North Korean ambassador's statements."

He points out that the youth wing of the United Malays National Organization (UMNO) - the main party in the ruling coalition - is planning a demonstration in front of the North Korean embassy on Thursday, February 23.

"Few Malaysians have any stake in the relationship, so there's unlikely to be any sympathy for the North Koreans."