Kim Jong-nam, a 46-year-old jovial playboy with a penchant for women and gambling, arrived early at Kuala Lumpur airport's low cost terminal for his 10.50am flight on Monday to Macau, where he lived under Chinese protection with his second wife and son.

The assassins chose a well-lit spacious departures hall lined with cafes such as Starbucks, and a Chinese new-year exhibit featuring a giant yellow chick, to attack the half-brother of North Korea's tyrant leader Kim Jong-un.

There are numerous security cameras on walls around the hall that is almost always packed with budget travellers.

Police who have viewed CCTV footage say Mr Kim was approached by two Asian-looking women.

One touched his face with a cloth that contained an unidentified liquid while the other sprayed him with substance believed to be poison.

The attack lasted no more than 15 seconds.

The nearest CCTV camera was not working but another further away showed him going into a nearby toilet, where he washed his face, before walking to a check-in counter, where he asked for police, witnesses said.

Mr Kim was given directions to a police post.

What he told them is not known but he had, by then, become dizzy and unwell, and was escorted to an airport medical clinic.

An ambulance was called but he died on the way to hospital.

The women attackers made no attempt to disguise their appearances to the security cameras.

One was captured outside the terminal wearing a white top with "LOL" emblazoned on it on Wednesday.  A second woman was arrested on Thursday.

If Malaysian authorities were not aware that Mr Kim was a frequent visitor to Malaysia, where one Korean news outlet said he had a "woman friend", they soon realised they had a James Bond-type assassination on their hands, despite the fact he was travelling on a North Korean passport under the name Kim Chol.

Malaysia is one of a dwindling number of countries that maintains close relations with North Korea, a pariah state condemned by the United Nations for conducting nuclear and ballistic missile tests.

Police kept the killing under wraps until late on Tuesday.

South Korea's spy agency, which has a long history of portraying North Korea's leader as mentally unstable, swiftly blamed the assassination on North Korean spies, who are known to have carried out numerous assassinations and kidnappings around the world.

The woman who was captured on CCTV footage leaving the airport on Monday with her companion in a taxi, returned to the airport on Wednesday, shortly after 8am. She was quickly identified and arrested.

Police said she was planning to catch a flight to Vietnam. She was carrying a Vietnamese passport identifying her as 28-year-old Doan Thi Huong, born in 1998 in Nam Dinh, a city in the Red River Delta of northern Vietnam. The second woman was carrying an Indonesian passport, police said. Police have not said whether the passports are genuine.

Some media outlets have reported the woman told interrogators how she and her companion were convinced to carry out a "prank" on a passenger friend of four men who she met later at a hotel in Bandar Salak Tinggi, near the airport. But the men and her female companion abandoned her and she decided to return to the airport, she claimed.

On Wednesday, Malaysia's Police Deputy Inspector-General Noor Rashid Ibrahim told reporters "police are looking for a few others, all foreigners," suggesting police were giving weight to at least part of her story relating to four mysterious men.

Since Monday there have been frequent comings and goings from North Korea's embassy in Kuala Lumpur but no-one from there has said anything to a waiting throng of reporters camped outside.

There has also been silence from Pyongyang, which is not surprising given the country's propaganda specialists are masters at reporting only details that lionise the Kim family as paragons of virtue.

North Korea did, however, try to convince Malaysian authorities not to carry out an autopsy on Mr Kim's body and asked for it to be immediately handed over to North Korean officials.

Malaysian authorities carried out the autopsy anyway late on Wednesday.

The assassination has prompted a flurry of speculation about the motive.

South Korea's spy agency told lawmakers that the north had been trying to kill Mr Kim for five years and there had been previous botched attempts. They offered a single motive: Kim Jong-un's paranoia over his estranged older half-brother.

Only last week a South Korean newspaper reported that Kim Jong-nam tried to defect to the south in 2012.

According to accounts mainly from the south, hundreds of people perceived to be disloyal to Kim Jong-un have been executed or purged since he assumed power after the death of his father five years ago

Malaysian police have so far failed to get the bottom of how Malaysian Airlines flight MH370 with 239 people on board disappeared on a flight from Kuala Lumpur in March 2014.

Will they now be able to piece together who was behind one of the most audacious assassinations in recent Asian times?