KUALA LUMPUR, Malaysia (WN)The Malaysian police said on Wednesday that a senior diplomat in the North Korean embassy was wanted for questioning in the killing of Kim Jong-nam, pointing to possible government involvement in the fatal poisoning of the estranged half brother of Kim Jong-un, North Korea’s leader.

At a news conference in which investigators gave their fullest public account to date of the killing, the police also said the attackers had been trained to wipe toxins on the face of the half brother, Kim Jong-nam, and then wash their hands after the attack at the Kuala Lumpur airport on Feb. 13.

The revelations are sure to escalate pressure on North Korea over a killing that South Korean officials have branded “a terrorist attack” and to further inflame Malaysia’s relations with the North. Pyongyang has refused to acknowledge that the man killed was Kim Jong-nam and has accused Malaysia of carrying out a politically motivated investigation.

Kim Jong Nam, the estranged half-brother of North Korean leader Kim Jong Un, was killed at Kuala Lumpur International Airport on Feb. 13 while he was preparing to board a flight to Macau.

Khalid told a news conference that police "strongly believed" four other suspects who fled Malaysia on the day of the attack, had gone to the North Korean capital of Pyongyang. Last week, Malaysian police arrested a North Korean man and two women from Vietnam and Indonesia.

Khalid said both woman wiped a liquid, containing an as yet unidentified toxic substance, on Kim Jong Nam's face. "Yes, the two female suspects knew that the substance they had were toxic. We don't know what kind of chemical was used," he said.

"They used their bare hands," he said, adding they were instructed to wash their hands afterwards. Khalid said police will apply to extend the suspects remand in custody.

Diplomatic tensions have escalated between North Korea and Malaysia since the killing, with the countries tussling over custody of the victim's body and trading barbs over Malaysia's handling of the investigation.

Malaysia is one of the few countries in the world that maintains ties with the nuclear-armed nation. Khalid Abu Bakar, the police inspector general, said Wednesday that North Korean officers had put toxins on the hands of the two female attackers, one of whom has been identified as Vietnamese and the other Indonesian.

He said seven North Koreans were now suspected of being involved in the attack, with four having fled to their homeland and two others the embassy official, identified as the second secretary at the embassy, and an employee of the North Korean airline Air Koryo still believed to be in Malaysia.

North Korea has rejected any assertion that the deceased is the half brother of North Korea’s leader. North Korea has instead identified him as Kim Chol, saying he held a diplomatic passport and rejecting Malaysia’s efforts to involve the victim’s family in identifying the body.

North Korea has called the Malaysian investigation into the killing and the autopsy politically motivated and demanded that its own government take part in the inquiry.