She and Indonesian Siti Aisyah allegedly smeared banned chemical weapon VX nerve agent on Kim Jong-nam's face and he died within minutes. They claimed that they believed it was part of a prank show.

The sources said that Ri worked as a trainee diplomat at the North Korean Embassy in Vietnam for more than one year in November 2009. He worked as an interpreter as well.

Ri is among four North Korean suspects who fled Malaysia on the day of Kim's death and are believed to have returned to Pyongyang.

Malaysian police said that eight North Koreans were suspected of being involved in the murder along with the two Asian women.

They are looking for three North Korean suspects, including diplomat Hyon Kwang-song.

Ri and Ri Jae-nam, a 57-year-old North Korean suspect, are believed to have visited Vietnam last December in a bid to find a Vietnamese citizen to join the plot to kill Kim Jong-nam, the sources said.

They are known to have made a trip to Cambodia with Huong in order to go through trial runs with her prior to what she believed to be a show, which was in reality the murder, they added.

Japan's broadcaster NHK reported that O Jong-gil, a 55-year-old North Korean suspect, appears to be a diplomat who worked as the second secretary at the North Korean Embassy in Indonesia.

The Indonesian suspect is believed to have held similar practice runs at a different place in Cambodia after being convinced to join the plot by North Koreans probably including O.

He is also known to be fluent in the Indonesian language.

Malaysian police said that the two female suspects were aware that they took part in the attack and the substance they had was toxic. (Yonhap)