Amid the mystery surrounding the assassination of the estranged half brother of North Korean leader Kim Jong Un, sources said Wednesday that a North Korean suspect involved in the murder of Kim Jong Nam is the son of a former top North Korean envoy to Vietnam. Ri Ji Hyon, 33, the suspect, apparently persuaded an Asian woman to commit the murder, which took place in Malaysia on Feb. 13, by talking fluent Vietnamese, Yonhap News Agency reported.

Ri had lived in Vietnam for about 10 years, sources said. He previously worked as a trainee diplomat at the North Korean Embassy in Vietnam for more than a year in November 2009. The fluency in Vietnamese language allegedly helped him convince Doan Thi Huong, a Vietnamese, into killing Kim Jong Nam. Huong and another Indonesian woman, Siti Aishah, allegedly killed him by smearing the banned chemical weapon VX nerve agent on his face, according to Yonhap.

Read: After Kim Jong-Nam, Will His Son Be The Next Assassination Target?

Regarding the controversy surrounding the lapse in Malaysia's national security surveillance systems that resulted in Kim Jong Nam's murder, Malaysia's Home Ministry has denied so. Deputy Home Minister Nur Jazlan Mohamed said in parliament Monday that the government had no clue about Kim entering its soil as he had used a passport with a different name Kim Chol, according to Channel News Asia.

The two woman suspects — Aishah, a mother of one from Jakarta, and Huong, from rural northern Vietnam — face mandatory death sentence if they get convicted for the killing, reports said. 

The CCTV footage, which was released after the assassination, allegedly showed two women approaching Kim Jong Nam at Malaysia airport and rubbing a cloth over his face, after which he died within 20 minutes.

Apart from these two women, Malaysian police had also identified eight North Koreans, who were wanted for questioning in connection with Kim Jong Nam's murder. Some of those are hiding in the North Korean embassy. Last week, police said the Interpol issued a "red notice," the closest to an international arrest warrant, for four North Koreans wanted in connection with the murder, reports said.