Mr Kim Jong Nam, the half-brother of North Korea's leader, died within 20 minutes of poisoning by the quick-acting VX nerve agent, said the Malaysian health authorities.
As details of his last moments emerged, the Health Ministry said that, as the poison took effect quickly, it was unlikely that Mr Kim could have survived even with medical aid. It would have been a swift but painful death, it said.
Early yesterday morning, Malaysian personnel clad in hazmat suits swept the airport where Mr Kim was killed for possible traces of the poison. The area was declared safe.
Police said last Friday that Mr Kim, 45, was killed by the VX nerve agent, a chemical warfare weapon banned under the United Nations Chemical Weapons Convention.
Health Minister Subramaniam Sathasivam, speaking to reporters yesterday, said: "It (VX) acted so fast that all organs were affected. VX requires only 10mg to be absorbed into the system to be lethal. I presume the amount of (VX) was more than that."
He also said that, as the dose "was so high and lethal", it made treatment "very difficult".
Mr Kim was attacked on Feb 13 at Kuala Lumpur's budget terminal airport while waiting for his flight to Macau. Closed-circuit TV footage showed two women approaching him and wiping his face with a liquid that Mr Kim told airport staff was "dangerous". He was taken to the airport clinic, where he collapsed. He died on the way to hospital.
Datuk Seri Subramaniam told reporters that the autopsy report has been completed and will be handed to the police this week. He said the body remains to be identified.
Mr Kim was travelling under the name Kim Chol, as found in his passport. The North Korean Embassy insists the cause of death is "heart stroke" and refuses to acknowledge that the dead man is Mr Kim Jong Nam. South Korea has accused North Korean leader Kim Jong Un of ordering his brother's killing.
"Once we have identified the person and we have a next of kin, our job is done," Mr Subramaniam said.
Police have sent for testing chemical samples taken from an empty condominium unit last Thursday.
Four North Korean suspects wanted in connection with Mr Kim Jong Nam's death had rented the unit. Police said the four men fled the country immediately after the attack.
Police are looking for three other North Koreans believed to be still in Malaysia. One of them is embassy staff and another is an employee of North Korean airline Air Koryo. The third man reportedly recruited the Indonesian female suspect. The second female suspect is Vietnamese. Police have both women and a North Korean man in custody.
The authorities are trying to find out how the women escaped harm despite having handled the poison.