The co-pilot who attacked the captain had been previously banned from flying by Oman for radical views.

WSJ - The FlyDubai co-pilot who stabbed his captain and sent Flight 1073 diving toward the ground had previously been banned from flying by Oman over concerns he had adopted radical ideological views. https://www.wsj.com/world/middle-east/flydubai-attacker-had-been-banned-from-flying-by-oman-for-radical-views-ab363b5d?st=MnzfKV

FlyDubai Attacker Had Been Banned From Flying by Oman for Radical Views (Wall Street Journal) https://www.wsj.com/world/middle-east/flydubai-attacker-had-been-banned-from-flying-by-oman-for-radical-views-ab363b5d?st=MnzfKV http://www.memeorandum.com/261002/p100#a261002p100