KUALA LUMPUR, Malaysia — A man from North Korea has been arrested in Malaysia in connection with the murder of Kim Jong Nam, the North Korean leader’s half brother, in what South Korean officials have described as an assassination.

A diplomatic dispute erupted after South Korean observers suggested that the killing was possibly ordered by North Korean leader Kim Jong Un himself.

Saying the first autopsy had been inconclusive, Malaysian authorities said they would perform a second post-mortem to try to ascertain what killed Kim Jong Nam, whose was sprayed with liquid in a brazen attack at Kuala Lumpur airport and who died en route to the hospital.

The decision to carry out a second autopsy will anger North Korea, which strongly objected to the first one and is insisting on having the elder Kim’s body returned. It accused the Malaysian government of acting on the orders of South Korea to ‘‘conceal something.’’

In the latest development, a 47-year-old North Korean man was arrested at about 10 p.m. Friday in an apartment in Kuala Lumpur.

He was carrying an ‘‘I-Kad’’ — an official identification card issued to foreign workers — that said he was Ri Jong Chol, a citizen of North Korea, according to a statement from Khalid Abu Bakar, inspector-general of the Royal Malaysian Police.

Two women arrested last week and accused of carrying out the attack — one Vietnamese, the other Indonesian — led police to Ri, according to local news reports that cited police sources. The Indonesian suspect told investigators she was duped into thinking she was part of a comedy show prank.

The arrest of Ri will heighten suspicions that Kim Jong Un, the 33-year-old third generation leader of North Korea, ordered the assassination of his older half-brother to remove a potential rival to his power.

Police said they are still looking for three other ‘‘foreign’’ men suspected of coordinating the attack.

Kim Jong Nam, who has lived outside North Korea for about 15 years, was at Kuala Lumpur airport on Monday to check in for a flight to Macau, where he has a home and a family, when he was ambushed by two women who applied some kind of liquid to his face.

He sought help but died in an ambulance on the way to the hospital, while the two women reportedly escaped in a taxi driven by a Malaysian man, who has also been arrested.

According to reports, the Vietnamese woman, identified as 29-year-old Doan Thi Hoang, told police that she was tricked into taking part in the attack.

Indonesian newspapers offered a similar explanation for the other woman arrested, 25-year-old Siti Aishah.

One news outlet reported that she was approached by a mysterious man at the Kuala Lumpur nightclub and offered $100 to be involved in a ‘‘prank’’ that was rehearsed in the airport.

If North Korea was behind the killing, it was surprisingly amateurish for the regime, which has a history of using elite agents in such attacks. But the three suspects were quickly apprehended, with Doan Huong, apparently abandoned by the others, arrested when she returned to the same airport terminal to take a flight to Vietnam.

Local officials have said it is still too early to conclude that foreign agents had killed Kim Jong Nam as the investigation into the complicated case was ongoing, but South Korea’s intelligence chief had squarely laid the blame on Kim Jong Un, who he said had issued a ‘‘standing order’’ to have his half-brother killed.

The North Korean ambassador to Malaysia spoke to reporters outside the hospital morgue late Friday.

In his first public statement on the case, Kang Chol said North Korea would ‘‘categorically reject’’ the results of the autopsy, which he said was performed over its objections and with its officials excluded. He called for the body to be released immediately, without naming the victim.

Because Kim Jong Nam was traveling on a diplomatic passport — he had four of them — he was under North Korea’s consular protection, Kang said.

Using language usually reserved for enemies rather than relatively friendly Malaysia, Kang said the Malaysian government was acting on the orders of South Korea to ‘‘conceal something.’’

North Korea would ‘‘respond strongly to the moves of the hostile forces toward us with their intent to besmirch the image of our republic, by politicizing this incident’’ and would sue Malaysia in an international court, he said.

North Korea’s ruling Kim family is a highly secretive dynasty.

The totalitarian state tightly controls information about the family, which has kept a grip on the country for three generations: from Kim Il Sung, the founding president, through Kim Jong Il, the father of both Kim Jong Nam, who was 46, and the current leader, Kim Jong Un, who is 33.

Ordinary North Koreans, starved of outside information, do not know about the existence of Kim Jong Nam, the love child of a secret relationship between Kim Jong Il and his actress consort.