Kim Jong-nam told medics before he died that he was attacked with a chemical substance, South Korean media reports.
Malaysian police have detained a second woman believed to be connected to the death of Kim Jong-nam, the half-brother of North Korean leader Kim Jong-un, state media reported.
Police Inspector General Tan Sri Khalid Abu Bakar confirmed the detention on Thursday and said an official statement would be released later in the day, state news agency Bernama said.
On Wednesday, a woman carrying Vietnamese travel documents bearing the name Doan Thi Huong was arrested at Kuala Lumpur International Airport, the scene of Monday’s poisoning.
Police are also hunting for further suspects.
Kim died on Monday after suddenly falling ill at Kuala Lumpur airport. He had been on his way to the Chinese territory of Macau, where he had been living. He was reportedly living under China’s protection.
He died on his way to hospital.
An autopsy was to be performed on Wednesday, police said.
Police and authorities were working with diplomats from North Korea and Vietnam to confirm whether or not the suspect is a Vietnamese citizen, local media reported.
Al Jazeera’s Karishma Vyas, reporting from Kuala Lumpur, said police are looking for several others suspects, including four men who might be involved in the murder of Kim Jong-nam.
“Kim had lived in exile for many years and kept a low profile. He never publicly expressed interest in challenging his half-brother Kim Jong-un for the North Korean leadership, however, he has been critical of the regime. He did not support the dynastic style of the political rule [and] that may have been perceived as threat.”
South Korea’s spy agency suspects that two female North Korean agents assassinated Kim, South Korean MPs in Seoul have said.
“If the murder of Kim Jong-nam was confirmed to be committed by the North Korean regime, that would clearly depict the brutality and inhumanity of the Kim Jong-un regime,” South Korean Prime Minister Hwang Kyo-ahn, who is also the country’s acting president, told a security council meeting.
Al Jazeera’s Harry Fawcett, reporting from Seoul, said: “The National Intelligence Service here says this is a long-standing order from the North Korean leadership. There was [reportedly] an attempt in 2012 to kill him. There have long been efforts to eradicate this family member.”
While there was speculation over the timing of the incident, the head of Seoul’s spy agency has said that North Korea probably just made the most of an opportunity that presented itself, said Fawcett.
Kim, 46, was targeted in the shopping concourse at the airport and had not yet gone through immigration for his flight to Macau, said a senior government official, who spoke on condition of anonymity because the case involves sensitive diplomacy.
Kim told medical workers that he had been attacked with a chemical spray, the official said.
Although Kim had been tipped by some outsiders as a possible successor to his father, others thought that was unlikely because he lived outside the country, including recently in Macau, Singapore and Malaysia.