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The bizarre assassination of North Korean dictator Kim Jong Un's estranged half-brother -- a plot that appeared to be ripped straight out of a spy novel -- will reveal a new chapter Friday, when the two women accused of pulling off the caper are expected to plead not guilty to the crime.

Siti Aisyah, of Indonesia, and Doan Thi Huong, of Vietnam, are alleged to have smeared a liquid across Kim Jong Nam's face while he waited for a flight to Macau at the Kuala Lampur airport on Feb. 13.

The liquid was later identified as a banned VX nerve agent that authorities said killed Kim within “15-20 minutes.” Pyongyang is suspected of being behind the murder.

Nam killers

Indonesian suspect Siti Aisyah, left, and Vietnamese suspect Doan Thi Huong, are accused of killing Kim Jong Nam. (AP)

"VX only requires 10 milligrams to be absorbed into the system to be lethal, so I presume that the amount of dose that went in is more than that," Malaysian Health Minister Subramaniam Sathasivam told reporters in February. "The doses were so high and it did it so fast and all over the body so it would have affected his heart, it would have affected his lungs, it would have affected everything."

Kim died en route to the airport after falling ill at the airport.

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The women, who are the only suspects in the case and face a possible death penalty if convicted, claim they were duped into thinking they were playing a harmless prank on unsuspecting men for a hidden-camera TV show.

Aisyah, 25, was recruited by a North Korean man known as "James" in early January to star in prank videos, her lawyer, Gooi Soon Seong, has said.

Huong, 29, was caught on airport surveillance video on the day of the murder wearing a white jumper emblazoned with the letters "LOL" — an acronym for "laughing out loud."

Security video showed her lunging at Kim Jong Nam from behind in the crowded terminal.

two kims

Kim Jong Nam, left, is Kim Jong Un's half-brother. (AP)

A South Korean spy agency said the assassination was part of a five-year plot by Kim Jong Un to kill a brother he reportedly never met. Four North Korean suspects fled the country, police say.

North Korea has a long history of ordering killings of people it views as threats to its regime. Kim Jong Nam had spoken out publicly against his family’s dynastic control of the nuclear-armed nation.

North Korea has refused to publicly accept that the dead man was the leader’s half-brother and has suggested the victim died of a heart attack. It has accused Malaysia of working with South Korea and other "hostile forces" in blaming the North.

Kim Jong Nam, who was 45 or 46, had been living abroad for years. He reportedly fell out of favor when he was caught trying to enter Japan on a false passport in 2001, saying he wanted to visit Tokyo Disneyland.

The Associated Press contributed to this report.