The suspect, identified as Chang Nam Un, is said to be in his early 30s, and was with four other agents who kept watch in the concourse of Kumpur Lumpur International Airport while two women carried out the brazen attack against the estranged half-brother of North Korea leader Kim Jong Un on February 13.
When authorities in Malaysia were identifying the body of Kim Jong Nam, the late half-brother of North Korean leader Kim Jong Un, after he was poisoned last month, their evidence was golden - literally. He didn't say when and where the DNA sample was taken.
A Vietnamese woman and an Indonesian woman have been charged in the case.
North Korea is preventing three Malaysian diplomats and their six family members from leaving the country, sparking tit-for-tat action by Malaysia. Pyongyang announced it would stop Malaysians from leaving North Korea, a move that Prime Minister Najib Razak condemned.
Although Malaysia has never directly accused North Korea of being behind the attack, some analysts speculate that it orchestrated it. North Korea - widely suspected of being behind the attack - rejects the findings. The chemical is so toxic it is on the United Nations list of weapons of mass destruction.
North Korea has denied any wrongdoing in the incident and has denied the man was even Kim Jong Nam, referring to him only as Kim Chol, the name on the passport of the man who was killed. He had spoken out publicly against his family's dynastic control of the isolated, nuclear-armed North Korea.
The number of countries that North Koreans can travel to visa-free has been reduced to 39 this year, a U.S. broadcaster said Wednesday.
Both countries also scrapped visa-free travel for each other's citizens.
A leading regional security expert told the AFP news agency last month that it would not have been hard to get VX into Malaysia in a diplomatic pouch, which would not be subject to regular customs checks.
He said anyone including North Korea could ask for such inquiry.
Japan also offered data on Kim Jong-nam's physical characteristics, such as fingerprints and mug shots, the sources said.
"I again confirm that it is Kim Jong Nam".