Kim Jong-nam, the half-brother of North Korea's leader, was killed by a highly toxic nerve agent, says Malaysia.
Mr Kim died last week after two women accosted him briefly in a check-in hall at a Kuala Lumpur airport.
Malaysian toxicology reports indicate he was attacked using "VX nerve agent", which is classified as a weapon of mass destruction by the United Nations.
Malaysia has not blamed the North Korean state for the death, but says North Koreans were clearly behind it.
Mr Kim died on the way to hospital shortly after the 13 February airport encounter. His body remains in a hospital mortuary, amid a diplomatic dispute over who should claim it.
North Korea responded furiously to Malaysia's insistence on conducting a post-mortem examination and has accused Malaysia of having "sinister" purposes.
VX nerve agent: What to know
The most toxic of the known chemical warfare agents, it is a clear, amber-coloured, oily liquid which is tasteless and odourless.
Works by penetrating the skin and disrupting the transmission of nerve impulses - a drop on the skin can kill in minutes. Low doses can cause eye pain, blurred vision, drowsiness and vomiting.
It can be disseminated in a spray or vapour, or used to contaminate water, food, and agricultural products.
VX can be absorbed into the body by inhalation, ingestion, skin contact, or eye contact.
Clothing can carry VX for about 30 minutes after contact with the vapour, which can expose other people.
Official chemical name is S-2 Diisoprophylaminoethyl methylphosphonothiolate and it is banned by the 1993 Chemical Weapons Convention.
Malaysia's police chief Khalid Abu Bakar said the presence of the nerve agent was detected in swabs taken from Mr Kim's eyes and face by the Chemistry Department of Malaysia.
He said other exhibits were still under analysis and that police were investigating how the banned substance might have entered Malaysia.
"If the amount of the chemical brought in was small, it would be difficult for us to detect," Reuters quoted him as saying.
Bruce Bennett, a weapons expert at the research institute the Rand Corporation, told the BBC it would have taken only a tiny amount of the substance to kill Mr Kim.
A miniscule amount of nerve agent could have been used, said Mr Bennett, which would have begun affecting his nervous system immediately, causing first shaking and then death within minutes.
The two women were seen in CCTV footage approaching Mr Kim, with one wiping something across his face.
Mr Khalid has previously said the fact the woman immediately went to wash her hands showed she was "very aware" that she was handling a toxin.
She and another woman are in custody.
Several North Koreans are also wanted in connection with his death, including a senior official at the North's embassy in Kuala Lumpur as well as an employee of the state airline, Air Koryo.
Four other North Koreans named earlier in the case are thought to have left Malaysia already, while a fifth North Korean has been detained.
Mr Kim was once seen as a possible successor to his father, Kim Jong-il, but was bypassed in favour of his younger half-brother, Kim Jong-un, and spent many years living abroad.
He had been travelling on a passport under the name Kim Chol. North Korea has yet to confirm that the deceased was actually Kim Jong-nam.
On what seemed to be the first reference to the case in the North's state media, Pyongyang said on Thursday only that Malaysia was responsible for the death of one of its citizens.
It also accused Malaysia of trying to politicise the return of his body and called "absurd" Malaysia's request for DNA samples for official confirmation of his identity.
Who are the suspects?
Detained
Doan Thi Huong, 28, Vietnamese, one of two women suspected of wiping toxins on Mr Kim's face. She is thought to be the woman seen in CCTV footage wearing a white top emblazoned with the letters "LOL".
Siti Aisyah, 25, Indonesian, the other female suspect. Indonesian authorities say she claims she thought she was taking part in a TV prank.
Ri Jong Chol, 47, a North Korean.
Muhammad Farid Jalaluddin, the Malaysian boyfriend of Siti Aisyah.
Sought for questioning
Hyon Kwang Song, 44, second secretary at the North Korean embassy in Kuala Lumpur. Believed to still be in Malaysia.
Kim Uk Il, 37, staff member of North Korea's state airline Air Koryo. Believed to still be in Malaysia.
Ri Ju U, 30, a North Korean also known as "James". Believed to still be in Malaysia.
Ri Ji Hyon, 33, a North Korean. Believed to have fled to Pyongyang.
Hong Song Hac, 34, a North Korean. Believed to have fled to Pyongyang.
O Jong Gil, 55, a North Korean. Believed to have fled to Pyongyang.
Ri Jae Nam, 57, a North Korean. Believed to have fled to Pyongyang.
17.12°C Kathmandu
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