Updated

Malaysian police on Friday released the only North Korean detained in the killing of the half brother of North Korea's leader, and later said an arrest warrant had been issued for another whose whereabouts are unknown.

Malaysia is looking for seven North Korean suspects in all, four of whom are believed to have left the country Feb. 13, the day Kim Jong Nam died. The only people in custody are two women — one Indonesian, one Vietnamese — accused of smearing his face with the banned nerve agent VX.

Ri Jong Chol, who had been detained since Feb. 17, was handed over to immigration officials for deportation. Police never said what they thought his role was in the attack, but national police chief Khalid Abu Bakar confirmed Friday that Ri was released due to a lack of evidence against him.

Malaysian Attorney General Mohamad Apandi Ali earlier said Ri would be deported because he lacked valid travel documents. Immigration director Mustafar Ali said Ri would be escorted by two representatives from the North Korean Embassy.

The women charged with murdering Kim at an airport terminal were caught on grainy surveillance video smearing what Malaysian authorities say was VX nerve agent on his face and eyes, though both reportedly say they were duped into thinking they were playing a harmless prank.

Four of the North Korean suspects police seek are believed to have left Malaysia the day Kim, the estranged half brother of North Korean leader Kim Jong Un, was killed. One of the suspects believed to still be in Malaysia is an official at the North Korean Embassy.

Khalid said the arrest warrant issued Friday was for 37-year-old Kim Uk Il, who works for Air Koryo, North Korea's national carrier. Police say he arrived in Malaysia on Jan. 29, about two weeks before Kim Jong Nam was attacked.

Malaysian authorities have not said why they want to question Kim Uk Il, but they believe he also is still in Malaysia.