Officials say Mohammed Hamzah Khan allegedly supported overseas terrorism and was attempting to join ISIS.

Prosecutors say he attempted to board a flight to Turkey with a round-trip ticket with intents of crossing into neighboring Syria or Iraq to join ISIS.

A legal analyst adds, the F.B.I. was ready the moment Khan got to the airport and had executed a search warrant at his house, proving this was an ongoing investigation.

A complaint affidavit says law enforcement agents observed Khan pass through security at O'Hare, and then arrested him. 

Federal agents allegedly recovered multiple handwritten documents expressing support for ISIS, when they searched Khan's home.

Those plans, according to the affidavit, included those travel plans to Turkey. 

In court Monday, he was charged with one count of attempting to provide material support to a foreign terrorist organization. 

Khan is in federal custody pending a detention hearing Thursday morning.