Kuala Lumpur,  Detectives probing the assassination of Kim Jong-Un’s half-brother want to question a North Korean diplomat, Malaysia’s top policeman said today.

Investigators have put five North Koreans in the frame for last week’s brazen killing of Kim Jong-Nam at Kuala Lumpur International Airport and have said they are seeking three more for questioning.

They include the embassy’s second secretary, Hyon Kwang Song, as well as a North Korean airline employee called Kim Uk Il, Khalid Abu Bakar told reporters.

“We have written to the ambassador to allow us to interview both of them. We hope that the Korean embassy will cooperate with us and allow us to interview them quickly. If not, we will compel them to come to us,” he said.

Jong-Nam died last Monday after being attacked as he waited for a plane to Macau.

Leaked CCTV footage from the airport shows the chubby 45-year-old being approached by two women, one of whom grabs him from behind and appears to shove a cloth in his face.

Moments later Jong Nam is seen seeking help from airport staff, who direct him to a clinic, where he apparently slumped in a chair.

Malaysian police say he suffered a seizure and died before he reached hospital, seemingly from the effects of some kind of toxin.

Seoul has said from the start that Pyongyang was behind the murder, citing a “standing order” from Jong-Un to kill his elder sibling, and a failed assassination bid in 2012.

Asked whether the five North Korean suspects had masterminded the attack, Khalid said he believed they were “heavily involved” in the murder.

Four of the men fled the country on the day of the killing and returned to Pyongyang, he said, while one remains in custody in Malaysia.

The police chief dismissed claims the two women had believed the attack was a made-for-TV prank.

“Of course they knew” it was a poison attack, Khalid said. “I think you have seen the video, right? The lady was moving away with her hands towards the bathroom. She was very aware that it was toxic and that she needed to wash her hands.”

Khalid said Vietnamese suspect Doan Thi Huong, 28, and Indonesian Siti Aishah, 25, had been trained to swab the man’s face, practising in Kuala Lumpur before the attack at the airport.

Aishah wiped a toxic substance in his face first, followed by Huong, the Malaysian police chief said.

Khalid said investigators had been “very fair” and the North Korean embassy now had a duty to assist them.

Pyongyang and Kuala Lumpur have been at diplomatic daggers drawn over the attack, with North Korea’s envoy insisting Jong-Nam’s body be returned and objecting to an autopsy.

Malaysia rejected the request, saying the remains must stay in the morgue until a family member identifies them and submits a DNA sample. (AFP)