Malaysian authorities have detained a woman holding a Vietnamese passport in connection with the death of Kim Jong-nam, the half-brother of the North Korean leader, Kim Jong-un. 

The Malaysia inspector general said a 28-year-old woman, Doan Thi Huong, had been positively identified from CCTV footage and was alone at the time of her arrest. 

No other details were immediately available. Malaysian police were not available for comment. 

Earlier on Wednesday, South Korea’s spy agency said two women believed to be North Korean operatives had poisoned the 45-year-old exile in a shopping concourse at Kuala Lumpur international airport. 

Kim, who had not yet passed through security, was preparing to take a late-morning flight on Monday from the Malaysian capital to his home in Macau when he was allegedly attacked, according to South Korean MPs briefed by security services. 

The theory that Kim had been targeted by spies from the country he left more than 15 years ago gathered pace after Malaysian officials released a CCTV image purporting to show one of the alleged attackers as she waited for a taxi outside the airport shortly after the incident. 

The local Malay Mail newspaper also published a grainy photo of a woman it said was suspected by police of involvement in the killing. 

The image showed a young female, carrying a bag and wearing a white jumper that said “LOL” in large black print across the front. The Guardian has been unable to confirm if the woman is a police suspect. 

Kim, whose father was the late North Korean leader Kim Jong-il, claimed to have no political ambitions, but just weeks after his half-brother’s elevation to the leadership in late 2011 he told the Japanese journalist Yoji Gomi that the world would view his leadership as a “joke”. 

Two years earlier, he told Japan’s TV Asahi that he "personally opposed" the hereditary transfer of power in his family. 

South Korean intelligence officials claimed the regime had been planning his assassination for five years, but did not explain why they thought that was the case. 

Kim Jong-nam had told airport workers that someone had attacked him "from behind" and sprayed him in the face with an unknown liquid. He died in an ambulance on the way to hospital. 

"He told the receptionist at the departure hall that someone had grabbed his face from behind and splashed some liquid on him," said Selangor state’s criminal investigation chief, Fadzil Ahmat, according to Malaysia’s The Star newspaper. 

"He asked for help and was immediately sent to the airport’s clinic. At this point, he was experiencing headache and was on the verge of passing out. At the clinic, the victim experienced a mild seizure. He was put into an ambulance and was being taken to the Putrajaya hospital when he was pronounced dead." 

Malaysian police initially confirmed the death of a 45-year-old North Korean man whom it identified from his travel document as Kim Chol, born in Pyongyang. "Investigation is in progress and a postmortem examination request has been made to ascertain the cause of death," an earlier statement said. 

The head of Kuala Lumpur hospital’s forensics department, Mohamad Shah Mahmood, was taking part in the autopsy, according to Agence France-Presse. 

Outside the forensics department, a black Jaguar sedan bearing the North Korean flag pulled up on Wednesday afternoon, followed by another vehicle. 

Two men who emerged from the vehicles declined to speak to waiting media as they entered the building. 

"The investigation is in progress. It covers everything including hunting down the possible suspects," said Abdul Samah Mat, the chief of police of Selangor state, which surrounds the capital.

Source :NNA