An 18-year-old from Denver was arrested at the airport on Monday after the Federal Bureau of Investigation said he was planning a trip to Afghanistan to join the terrorist organization ISIS. The teen and one of his relatives were preparing to board a flight to Sharjah, United Arab Emirates at the time he was arrested, according to a criminal complaint. The complaint says the FBI first began investigating the teen in November 2021 after some of his social media posts were flagged for declaring support for ISIS. Read more: https://www.9news.com/article/news/crime/colorado-teen-arrested-isis/73-9c9ed3f0-44c5-4568-bc65-6d99b3a2709a ----- More local videos here: https://youtube.com/@9news Subscribe to NEXT: https://youtube.com/@Nexton9NEWS Stay connected: 9NEWS Website: https://www.9news.com/ Facebook: https://www.facebook.com/ilike9news Twitter: https://twitter.com/9NEWS Instagram: https://www.instagram.com/9newsdenver/ Download the 9NEWS App: https://www.9news.com/appredirect/ Sign up for the 9NEWSLETTER: https://www.9news.com/email 9NEWS (KUSA) is located in Denver, Colorado.