Malaysia is going after several newly identified individuals, including an "important person", to assist in investigations into the alleged Feb 13 murder of Mr Kim Jong Nam, which has sparked a heated row with Pyongyang.
Inspector-General of Police Khalid Abu Bakar told reporters yesterday that the individuals included North Korean nationals, but did not disclose who they were.
Mr Kim is believed to have been assassinated on the orders of his estranged half-brother, North Korean leader Kim Jong Un.
"I won't deny that there are a few other North Koreans involved in the Kim Jong Nam murder and we will use legal channels to access them," Tan Sri Khalid was quoted as saying by state news agency Bernama.
However, he did not disclose their identities so as not to jeopardise investigations.
Mr Khalid said Pyongyang has yet to offer any assistance in tracking down four North Korean suspects who are believed to have fled Malaysia shortly after Mr Kim was killed at the Kuala Lumpur International Airport.
Police have arrested two women and two men. The men were later released. North Korean Ri Jong Chol, whose Malaysian work permit was obtained under false pretences, was deported after his two-week remand ended.
The women - Indonesian Siti Aisyah and Vietnamese Doan Thi Huong - have been charged with murdering Mr Kim by smearing VX nerve agent on his face.
VX is considered a weapon of mass destruction by the United Nations. North Korea is one of just four UN members not party to the Chemical Weapons Convention, which bans its use.
Seven other known persons of interest are North Korean, including the four fugitives and a senior diplomat believed to be hiding out with two others at their embassy in Kuala Lumpur.
Interpol has issued a red notice to track down and arrest the four men whom police believe supplied VX to the two women.
Pyongyang insists that the dead man is not related to its leader but is a citizen named Kim Chol travelling on a diplomatic passport.
It also claims the cause of death was a "heart stroke" and accuses Malaysia of conspiring with its enemies to tarnish its image.