The trial heard dramatic testimony from a policeman who said Kim Jong-Nam complained of having blurred vision after the attack at Kuala Lumpur airport before collapsing in a clinic as medics fought to save his life.
Indonesian Siti Aisyah and Vietnamese Doan Thi Huong, who arrived at Monday's hearing handcuffed and in bulletproof vests, were arrested just days after the killing of Kim on February 13 as he waited to board a plane to Macau.
The women are accused of rubbing toxic VX nerve agent, a chemical so deadly it is listed as a weapon of mass destruction, on his face.
Kim died an agonising death about 20 minutes after the hit, which was caught on airport CCTV as the VX rapidly shut down his central nervous system.
The defendants -- who face death by hanging if convicted -- claim they were duped into believing they were taking part in a prank for a reality TV show.
The murder sparked an angry row between North Korea, which was accused of masterminding the killing of Kim Jong-Un's estranged relative, and Malaysia, historically one of Pyongyang's few allies.
The women were led into the heavily guarded High Court in Shah Alam, outside the capital Kuala Lumpur, in handcuffs for the start of the trial. Aisyah, 25, was wearing traditional Malaysian dress and Huong, 29, a blue jumper.
The murder charge was read to them in their native languages and interpreters indicated they were pleading not guilty.
'Intention to kill'
Opening the prosecution, Muhamad Iskandar Ahmad said the women's actions showed their "intention to kill" and described how they had practised for the hit before carrying it out for real.
Four other suspects are accused in the charge sheet of killing Kim alongside the women, although they are still at large and authorities have not released their names. Four North Korean suspects fled Malaysia on the day of the murder.
The prosecutor said that before the murder Aisyah and Huong had carried out "prank simulations" which were "overseen by the four who are still free".
"The prank exercises... were a preparation by all of them to cause the death of the victim," he said.
Defence lawyers argued the charge was ambiguous due to the failure to identify the four other suspects, and urged the court to reveal their identities. Judge Azmi Ariffin refused the request.
The women's lawyers believe the four unnamed individuals are the main suspects in the murder.
'My eyes are blurred'
Witness Mohamad Zulkarnian, a police officer who was on duty at the airport budget terminal, described how Kim was brought to him by an official after the attack and how his eyes were red and surrounded by liquid.
As they walked to a medical clinic, Kim urged the police officer to slow down.
"Sir, walk slow, my eyes are blurred, I cannot see," Zulkarnian, 31, quoted Kim as saying.
The policeman waited outside the clinic after escorting Kim.
"I noticed the man slumped on a chair and the medical staff were giving emergency treatment to the victim," he said.
Zuliana Idris, an airport information officer who was the first person Kim approached after the attack, testified that he told her two women had attacked him from behind.
South Korea accuses the North of ordering the murder of Kim, who had voiced criticism of the regime after falling from grace and going to live in exile overseas. Pyongyang denies the allegations.
As well as the North Koreans who fled immediately after the assassination, several others allegedly linked to the murder plot were allowed to leave the country later to ease a diplomatic crisis.
Prosecutors -- who insist the women will get a fair trial -- will lay out their case over two months and call 30 to 40 witnesses. The defence is then likely to be called.
Before the murder Malaysia had been one of Pyongyang's few allies amid a global outcry over the country's atomic weapons programme.
After the assassination sent diplomatic relations plummeting between Pyongyang and Kuala Lumpur, tensions only eased when Malaysia agreed to return Kim's body in March.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)
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