A Malaysian government chemical weapon expert on Thursday testified that he found traces of a banned poison on the clothes worn by two women accused of murdering North Korean leader Kim Jong-un’s estranged half-brother in February. Raja Subramaniam told this to a Malaysian court as trials in the assassination case are under way, Reuters reported.

Subramaniam said he had found traces of VX, a chemical poison, in multiple forms – including the pure and a precursor form – on the clothes of the two women.

“The presence of precursors and VX [the pure form] confirms the presence of VX itself,” the expert told the court, according to Reuters. “I also found degradation products of VX, which confirms the presence of VX.”

Siti Aisyah of Indonesia and Doan Thi Huon of Vietnam have been charged with spraying VX on Kim Jong-nam’s face at the Kuala Lumpur airport on February 13. The two accused had on Monday pleaded not guilty of the assassination.

The two women, who face death penalty if convicted, have claimed that they were tricked by North Korean agents into smearing Kim Jong-nam’s face with the toxic agent. The women had told their lawyers that they were asked to carry out the act as part of a prank for a reality TV show, Reuters reported.

The trials will resume on Monday.