A Vietnamese woman who stood trial for the assassination of the North Korean leader's half-brother arrived home Friday, bringing down the curtain on a dramatic and often bizarre two-year murder mystery.

A Vietnamese woman accused of killing the half-brother of North Korean leader Kim Jong Un will walk free on May 3, her lawyer said Saturday.

Malaysia's prime minister said Tuesday the surprise release of an Indonesian woman who was on trial for assassinating the North Korean leader's half-brother followed the "rule of law", after suspicions of meddling amid an intense lobbying effort by Jakarta.

An Indonesian woman accused in the 2017 chemical poison murder of the North Korean leader's half-brother was freed on Monday after a Malaysian court dropped a murder charge in a case that drew suspicions of being a political assassination.

A Malaysian court on Tuesday suspended the trial of a woman accused of killing the half-brother of North Korea's leader as her lawyers sought more time to seek written statements from witnesses.

Judge Azmi Ariffin said the evidence presented in court since the trial started in October pointed to a "well-planned conspiracy" with a group of North Korean suspects who are still at large.

The laboratory that tested the nerve agent allegedly used to assassinate the North Korean leader's half-brother was not on the list of centres approved by the global chemical weapons watchdog, a Malaysian court heard.

The United States formally concluded Tuesday that North Korea murdered Kim Jong Un's half-brother with the banned VX nerve agent, blasting Pyongyang for deploying a chemical weapon in a packed international airport.

A woman accused of killing the North Korean leader's estranged half-brother was hired for a prank television show by a suspect wanted by the Malaysian police just over a month earlier, her lawyer told a court on Tuesday.

Doan Thi Huong and Siti Aishah have been charged with murder for the February 13 killing of Kim Jong Nam, the estranged half-brother of North Korean leader Kim Jong Un.

Indonesian Siti Aisyah, 25, and Doan Thi Huong, 28, from Vietnam, are charged with murdering Kim Jong Nam at the airport on February 13 by smearing his face with VX, a chemical.

Malaysia said on Saturday it was expelling the North Korean ambassador, escalating a diplomatic row between the two countries over the murder of the estranged half-brother of North Korean leader Kim Jong Un.