SHAH ALAM, Selangor - Traces of the deadly nerve agent VX were found on clothing of the two women accused of murdering Mr Kim Jong Nam, the half-brother of North Korea's leader, the Malaysian court heard on Thursday (Oct 5).

"We detect degradation product of VX, known as VX acid, on Siti Aisyah's sleeveless shirt, and two traces of precursors on the sleeve of a 'LOL' shirt," said Dr Raja Subramaniam, head of the Chemistry Department's Centre of Chemical Weapons and Analysis.

The government chemist's testimony was the first evidence in the murder trial which linked the two suspects to VX.

He explained that VX - which the United Nations classifies as a weapon of mass destruction - will degrade when it reacts with water, leaving detectable byproducts. Meanwhile a precursor is a chemical compound of the nerve agent, before a reaction takes place.

Traces of the nerve agent was also found on Vietnamese suspect Doan Thi Huong's fingernail, Dr Raja testified.

Doan, 28, was captured on closed-circuit television camera (CCTV) at the Kuala Lumpur International Airport wearing the "LOL" shirt on Feb 13, the day Mr Kim was attacked while waiting for his flight to Macau.

Doan and Indonesian Siti Aisyah, 25, had allegedly approached Mr Kim at the airport's departure hall and smeared VX nerve agent on his face.

A lab test found traces of VX nerve agent on Mr Kim's face, eyes, bag and the blazer he was wearing. Witnesses at the murder trial had earlier testified Mr Kim died from acute VX poisoning.

Dr Raja said pure VX, in its physical form, is colourless, odourless and tasteless. "A small drop of the nerve agent equal to about 10mg ... is enough to cause a fatal disruption to the nervous system ... If the decontamination process was carried out within 15 minutes of being in contact with VX, it would not cause a fatality," he added.

A person can fully decontaminate his or her hands of VX by washing and scrubbing with water, he said.

Earlier in the trial, which began on Oct 2, defence lawyers had questioned why those who attended to Mr Kim after he was attacked did not show symptoms of VX poisoning.

Dr Raja also agreed that the eye's mucous membrane was the best route of entry for the nerve agent as moisture would accelerate the process of contamination. He explained that the eye mucosa "has no barrier", and has lots of blood vessels compared to the palm, which has more fatty tissues.

"So, absorption is rapid through the eyes," he concluded.

Dr Raja is the eighth witness to testify in the murder trial of Mr Kim, who is the estranged half-brother of North Korean leader Kim Jong Un.

Both the suspects have claimed that they were duped into believing they were taking part in a prank for a reality TV show.

The trial will resume at the Shah Alam High Court on Monday (Oct 9).