It was all the culmination of an FBI undercover operation, and both men had been under FBI surveillance for months, charging documents say.
Hasan Edmonds first came onto the FBI’s radar in late 2014, and the FBI investigation began with an undercover agent sending him a "friend request" over Facebook, according to the charging documents. That agent and the 22-year-old, who joined the Illinois National Guard about three years ago, began exchanging messages online. At the same time, Hasan Edmonds had allegedly been watching ISIS propaganda videos online.
In one message to the undercover FBI agent, Hasan Edmonda allegedly wrote: "I’d rather struggle and strive hard in the cause of Allah ... than sit back and live a 'comfortable' life. ... The [Islamic] State has been established and it is our duty to heed the call."
He allegedly noted that while he is already in an army of non-believers, "now I wish only to serve in the army of Allah alongside my true brothers."
"Either we will make it to [the Islamic State] or bring the flames of war to the heart of this land," he wrote that day, according to charging documents.
In later conversations with the undercover agent, Hasan Edmonds allegedly said his cousin -- who first brought ISIS to his attention -- was willing to conduct an attack inside the United States. Jonas Edmonds was then approached by another undercover FBI agent, and in the following days the group discussed ways of getting to Syria or Iraq.
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.
Hasan Edmonds was arrested yesterday at Chicago's Midway airport. The FBI now has his luggage.
This case comes a week after a former U.S. Air Force veteran was indicted by federal authorities for allegedly trying to join ISIS.
On his laptop, FBI agents allegedly discovered more than 180 jihadist propaganda videos and noticed he had been conducting online searches for such phrases as "borders controlled by Islamic state," "kobani border crossing," and "who controls kobani."
Over the past 18 months, about 30 people have been charged with joining terrorist groups in Syria and Iraq or trying to do so.