Malaysia has requested Interpol to put an alert out for four North Korean suspects in the murder of Kim Jong Nam, half brother to North Korea leader, Kim Jong Un. Malaysia’s police chief Khalid Abu Bakar disclosed on Thursday that the police has sent an official request to the North Korean embassy in Malaysia to question the embassy’s second secretary and an official from North Korea’s national airline. The estranged half brother of North Korean leader Kim Jong Un was killed in Kuala Lumpur’s main airport last week, in what South Korean and U.S. officials say was an assassination carried out by North Korean agents.

Recall that Nam who is in his mid 40s was killed last week by persons believed to be North Korean assassins. He had spoken out publicly against the reign of his family in the country. Also, South Korean cable TV, Chosun reported that Kim was poisoned at the Kuala Lumpur airport. It said that two women believed to be North Korean operatives were responsible for the poisoning. The suspected women are now currently at large. Kim Jong Nam and Kim Jong Un are both sons of former leader Kim Jong Il, who died in late 2011, but they had different mothers. Kim Jong Nam was believed to be close to his uncle, Jang Song Thaek, who was North Korea’s second most powerful man before being executed on Kim Jong Un’s orders in 2013.