FBI officials arrested Iraqi-born American citizen Bilal Abood after discovering he may have traveled to Syria to fight for ISIS and then returned to the states.

Abood, who has been in America for six years, worked as an interpreter for the U.S. Army in Iraq.  Abood has been charged with lying to the FBI about the nature of his trip to Syria in 2013.  Abood originally told the FBI he was heading to Iraq to visit family, but later said he was going to Syria to fight with the Free Syrian Army against the Assad regime.  After seizing Abood's computers in July of 2014, the FBI said Abood watched ISIS propaganda videos, including beheadings, and found a Tweet by Abood pledging an oath to the leader of ISIS,

I pledge obedience to the Caliphate Abu Bakr al-Baghdadi. Here we renew our pledge to the Caliphate Abu Bakr al-Baghdadi.

Abood's arrest was a result of heightened scrutiny after the Garland, TX attack.  FBI Director James Corney instructed investigators to review cases of those already being tracked by the FBI to determine if more action was necessary, with Abood already at an advanced investigation state.

via CNN