Interpol on Thursday issued a red notice on four male North Korean suspects linked to the February murder of Kim Jong Nam.

The four men were charged with involvement in the murder of Kim Jong Nam last month, and all are thought to have left Malaysia soon after the attack was carried out.

Red notices are issued in support of national jurisdictions who want the persons concerned for prosecution, Interpol explains, adding that its role is to assist in identifying and locating these individuals. They are intended to “high, international visibility” to the suspects and to make international travel difficult by