According to authorities, the FBI arrested Army National Guard Specialist Hasan Edmonds, 22, at Chicago Midway International Airport as he was trying to fly to Egypt and join ISIS in Iraq or Syria.

They also arrested his cousin — Jonas Edmonds, 29, — at his home in Aurora, Illinois in connection with the incident.

Charging documents say the arrest was the final step in a month-long investigation that involved surveillance of the two suspects. In addition, they mentioned that the ISIS-wannabe came under official watch when — no joke — an FBI agent sent him a friend request on Facebook and he accepted. Facebook message exchanges between the two followed shortly thereafter.

In one of the messages, the National Guardsman allegedly wrote, “I’d rather struggle and strive hard in the cause of Allah … than sit back and live a ‘comfortable’ life. The State has been established and it is our duty to heed the call.”

He also mentioned that his cousin was prepared to conduct an attack inside the United States, and disclosed to an undercover agent exactly how he would escape to Iraq and Syria when he had the opportunity.

More on his plan from ABC News:

By Monday, the three had allegedly finalized a plan: Hasan Edmonds would leave the United States to join ISIS, and he would give his cousin his military uniform. Jonas Edmonds would then use AK-47s and grenades to attack the military installation where his cousin trained, according to charging documents.

Jonas Edmonds said he wanted a “body count” as high as 150, the charging documents say.

ABC News