
Ri Jong-Chol is among eight North Koreans suspected of involvement in the dramatic killing of Kim, the half-brother of the reclusive nation's leader, who was poisoned with a banned nerve agent at Kuala Lumpur International Airport.
Malaysia's attorney general has announced there was insufficient evidence to charge 47-year-old Ri and that he would be deported on Friday.
As he was led out of a police station outside the capital under tight security and handed over to immigration authorities, police chief Khalid Abu Bakar said he regretted the release.
"We believe that Ri Jong Chol played a part in Kim Chol's murder but unfortunately we lack evidence to charge him," he told AFP, using the name given in the passport carried by Kim Jong-Nam.
"We are frustrated because of a lack of evidence," he said via text message from Saudi Arabia where he is on a religious pilgrimage.