KUALA LUMPUR - The prosecution on Wednesday (Oct 4) presented in court samples taken from the urine, blood and liver tissues of Kim Jong Nam on the third day of his murder trial.

The prosecution said the VX nerve agent, which the United Nations has classified as a weapon of mass destruction, caused the death of the 45-year-old North Korean on Feb 13.

The victim's bag, T-shirt and underwear was also presented in court on Wednesday when the head of the Forensic Pathology Department at Hospital Kuala Lumpur, Dr Mohd Shah Mahmood, gave his testimony. He performed the autopsy on Kim Jong Nam.

A 11-page postmortem report, submitted as evidence in court on Tuesday (Oct 3), said traces of the deadly toxin and its precursor were found on his clothing, eyes, skin, urine and blood.

Reporters covering the closely-watched trial in the courtroom on Wednesday were asked to wear face masks to minimise the risk of exposure to VX, but this reporter found that not everyone wore a mask and gloves in court on Wednesday. Only some of the lawyers did.

Two women charged with his murder - Siti Aisyah, 25, from Indonesia, and Doan Thi Huong, 29, from Vietnam - pleaded not guilty at the start of the trial on Monday.

The prosecution has charged that the duo, using their bare hands, smeared Kim Jong Nam's face with VX at Terminal 2 of the Kuala Lumpur International Airport on Feb 13. They face the death penalty if found guilty.

The defence lawyers said on Monday the two suspects were duped by the North Koreans into thinking they were acting in a prank television show and had no idea who the victim was.

Malaysian police said four North Koreans are also suspects in the case which they suspect was an assassination masterminded by North Korean agents. Pyongyang has denied any involvement in the death of Kim Jong Nam, the estranged half brother of leader Kim Jong Un.

The four North Korean suspects flew out of Kuala Lumpur for Pyongyang on the day of the killing and remain at large.

A chemical pathologist called to the stand on Tuesday (Oct 3) said blood tests done on the two female suspects showed that their cholinesterase enzyme levels were normal while that for the victim was low.

Dr Nur Ashikin Othman agreed with defence lawyers that the normal readings could indicate that the two suspects were never in contact with any VX nerve agent, but she said it could also mean they were exposed to only low amount or that it was washed off quickly.

VX nerve agent blocks the enzyme cholinesterase, which in turn controls neurotransmitters that send signals to muscles and glands, allowing them to contract and relax normally.

The defence , which had earlier questioned if Mr Kim Jong Nam was killed by the VX nerve agent or by other means, on Wednesday again raised questions over the cause of his death.

Gooi Soon Seng, Aisyah's lawyer, questioned Dr Mohd Shah Mahmood's conclusion that Kim Jong Nam died of VX poisoning,

The defence lawyer cited heart failure or asphyxiation as possible causes of death, but argued that the doctor who performed the autopsy would not be able to tell whether the person was strangled, or poisoned or stabbed.

Referring to Dr Mohd Shah Mahmoo, Gooi said:"This is not for him to conclude, it's for the judge to decide if it was VX or not."

Two experts on toxicity are also expected to take the witness stand on Wednesday.