KUALA LUMPUR: North Korea's top envoy in Kuala Lumpur on Monday denounced Malaysia's investigation into the apparent killing of the exiled half brother of North Korea's ruler, calling it politically motivated and demanding a joint probe into the death. The comments from Ambassador Kang Chol came amid rising tensions between North Korea and Malaysia over the death, with Malaysia recalling its ambassador to Pyongyang over what it called 'baseless' allegations. Kim Jong Nam, the estranged half brother of North Korean ruler Kim Jong Un, died last week after apparently being poisoned in a Kuala Lumpur airport. Security camera footage obtained by Japanese television appeared to show a careful and deliberate attack in which a woman comes up from behind him and holds something over his mouth. Pyongyang demanded custody of Kim's body and strongly objected to an autopsy. The Malaysians still went ahead; an official with knowledge of the investigation said they conducted a second autopsy because the first was inconclusive, though police denied that. The official spoke on condition of anonymity because he was not authorized to speak to the media. Malaysian authorities say they were simply following procedures, but Kang questioned their motives. 'The investigation by the Malaysian police is not for the clarification of the cause of the death and search for the suspect, but it is out of the political aim,' Ambassador Kang Chol told reporters Monday. He referred to the dead man as 'Kim Chol,' the name on the passport found with Kim Jong Nam. Police had 'pinned the suspicion on us,' Kang said, calling on Malaysia to work with North Korea on a joint investigation. Malaysia Prime Minister Najib Razak told reporters later Monday that he has 'absolute confidence' that police and doctors have been 'very objective' in their work. Najib said Malaysia had no reason to 'paint the North Koreans in a bad light' but added, 'We expect them to understand that we apply the rule of law in Malaysia.' Kang previously said Malaysia may be 'trying to conceal something.' On Monday, the Malaysian foreign ministry said it had recalled its ambassador to Pyongyang 'for consultations' and had summoned Kang to a meeting, 'to seek an explanation on the accusations he made.' The statement called Kang's comments 'baseless' and said it 'takes very seriously any unfounded attempt to tarnish its reputation.' Police investigating the killing have so far arrested four people carrying identity documents from North Korea, Malaysia, Indonesia and Vietnam. Those arrested include two women who were allegedly seen approaching Kim on Feb. 13 as he stood at a ticketing kiosk at the budget terminal of the Kuala Lumpur airport. Surveillance video footage, obtained by Fuji TV and often grainy and blurred, seems to show the two women approaching Kim Jong Nam from different directions. One comes up behind him and appears to hold something over his mouth for a few seconds. Then the women turn and calmly walk off in different directions. More footage shows Kim, a long-estranged scion of the family that has ruled North Korea for three generations, walking up to airport workers and security officials, gesturing at his eyes and seemingly asking for help. He then walks alongside as they lead him to the airport clinic. Fuji TV has not revealed how it acquired the video footage, which was taken by a series of security cameras as Kim arrived for a flight to Macau, where he had a home. Kim, in his mid-40s, died shortly after the attack, en route to a hospital after suffering a seizure, Malaysian officials say. Malaysia's deputy national police chief, Noor Rashid Ibrahim, said Sunday that Kim had told airport customer service workers that 'two unidentified women had swabbed or had wiped his face with a liquid and that he felt dizzy.' Investigators are still looking for four North Korean men who arrived in Malaysia on different days beginning Jan. 31 and flew out the same day as the attack. 'I am not going disclose where they are,' Noor Rashid told a room packed with journalists. He said Interpol was helping with the investigation. The four suspects, who range in age from their early 30s to late 50s, were traveling on regular — not diplomatic — passports, he said. Indonesian officials said three of those men transited through Jakarta's Soekarno-Hatta International Airport after the apparent assassination, leaving on a 10:20 p.m. flight to Dubai. That was about 12 hours after the attack on Kim Jong Nam. Dubai police and the Dubai government media office did not immediately respond to requests for comment. State-owned airline Emirates declined to comment, citing policies on passenger confidentiality. Police also want to question three other people. Noor Rashid said one was North Korean, but that police had not yet identified the other two. It was not clear if they were suspects or simply wanted for questioning. Autopsy results on Kim Jong Nam could be released as early as Wednesday, said Health Minister S. Subramaniam. Investigators want to speak to Kim Jong Nam's next of kin to formally identify the body. He is believed to have two sons and a daughter with two women living in Beijing and Macau. 'We haven't met the next of kin,' Noor Rashid said. 'We are trying very hard to get the next of kin to come and to assist us in the investigation.' Noor Rashid said charges against the four suspects in custody would be determined by prosecutors. According to police, the Indonesian woman is a spa masseuse and the Malaysian man, a caterer, is believed to be her boyfriend. The Vietnamese woman works at an entertainment outlet and the North Korean man works in the information technology department of a Malaysian company. The Indonesian woman has told investigators that she was duped into thinking she was part of a comedy show prank. The Malaysian foreign ministry said the government has kept the North Korean Embassy informed, telling them that because 'the death occurred in Malaysian soil under mysterious circumstances, it is the responsibility of the Malaysian Government to conduct an investigation to identify the cause of death.' South Korea has been quick to blame North Korea for the death of Kim Jong Nam, who as the eldest son of the late dictator Kim Jong Il was once widely seen as the ruler-in-waiting of the isolated nation. However, he fell out of favor more than a decade ago, and has spent most of his time since then living in China or Southeast Asia. The attack 'showed the reckless and brutal nature of the North Korean government,' Prime Minister Hwang Kyo-ahn said Monday during a National Security Council meeting. A later statement from Hwang's office said South Korea will cooperate with the international community to make an unspecified 'strong' response to North Korea over the killing.