The three men, all in their 20s and related to each other, allegedly recorded videos pledging their allegiance to IS and discussed a potential car attack in the United States if one of them was unable to travel overseas to fight for the terror group.
FBI agents employed undercover agents to communicate with the suspects and multiple search warrants of their social media accounts to monitor the suspects' communications between each other, according to an affidavit filed in federal court.
The three were arrested Monday at Gerald Ford Airport in the city of Grand Rapids as Muse Abdikadir Muse, 23, also known as Muse Muse, was going through the TSA security screening process.
Authorities said he had checked in for a trip that would eventually take him to Mogadishu, Somalia, with the goal of joining IS.
In an online exchange with an undercover FBI agent, Muse allegedly said he wanted to join IS in Somalia and "fight in the front lines," according to the affidavit.
Police also arrested at the airport terminal the men said to be Muse's co-conspirators: his brother Mohamud Abdikadir Muse, 20, and another relative, Mohamed Salat Haji, 26.
The two are alleged to have purchased the airline ticket and driven Muse to the airport.
All three men, who are naturalized US citizens from Kenya, were charged with conspiring to provide material support or resources to a designated foreign terrorist organization.
Law enforcement became interested in the elder Muse starting in April 2016, when he allegedly publicly posted pro-IS messages on his Facebook account, the affidavit said.