VX nerve agent 'may not have killed Kim Jong Un's half-brother'

Lawyers for two women accused of murdering Kim Jong Un's half-brother in a Malaysian airport have disputed claims he was killed by a nerve agent.

Defendants Siti Aisyah and Doan Thi Huong allegedly wiped banned VX poison on Kim Jong Nam's face in an assassination thought to have been ordered by the North Korean leader.

Chemical pathologist Nur Ashikin Othman, who examined his body, said the victim had extremely low levels of an enzyme vital for nervous system function in his body, due to poisoning.

She said blood tests showed 344 units per litre of the cholinesterase enzyme, which breaks down neurotransmitters in the body that send signals to the brain and control the muscles.

The normal level is above 5,300 units per litre.

She explained a poison such as VX will inhibit enzyme levels, causing heart and lung problems and symptoms like profuse sweating and vomiting.

But she agreed with the defence that low enzyme levels could also have been due to other causes such as liver disease or if a man took female hormones.

"Yes, the enzyme levels could be slightly lower by the taking of hormone pills by a man," she said.

The pathologist also said it was possible the two murder suspects had no contact with VX as their blood samples showed normal levels of cholinesterase.

But they could have also been exposed to a low dose of the poison, washed their hands with soap and water or taken an antidote, she added.

In court in Shah Alam, near Kuala Lumpur, Malaysian government pathologist Mohamad Shah Mahmood said VX was found on Mr Kim's face and eyes, as well as in his blood, urine, clothing and bag.

A post-mortem showed Mr Kim suffered damage to his organs, including part of the brain, both lungs, his liver and spleen, the trial heard.

Mr Mahmood, who also examined his body, told the court "the cause of death is acute VX nerve agent poisoning" and there were no other contributing factors.

Indonesian Siti Aisyah, 25, and Vietnamese Doan Thi Huong, 28, have pleaded not guilty to murdering Mr Kim at Kuala Lumpur airport in February, saying they thought they were involved in a reality TV show prank.

The pair face the death penalty if convicted.