Abdo had disappeared from Kentucky's Fort Campbell after receiving word that he was going to be court-martialed for the possession of child pornography. Law enforcement personnel say he then drove to Texas and purchased bomb-making material for use in a planned attack on Fort Hood.
Abdo was arrested when a clerk at Guns Galore, a firearms store in nearby Killeen, grew suspicious of the young soldier's efforts to buy canisters of smokeless powder, which can be used in explosives. The clerk, Greg Ebert, alerted the Killeen police, who searched Abdo's room in a nearby motel and found enough components to build at least two bombs, according to a law enforcement official. The official said Abdo's room contained copies of the Quran and extremist literature, which appeared to have been downloaded from the Internet, though he didn't elaborate on the specific nature or source of the documents.
Killeen Police Chief Dennis Baldwin described Abdo as a "very dangerous individual" with the clear intent of attacking U.S. troops. "Military personnel were a target of this subject," he told reporters. "I would classifiy this as a terror plot."
Baldwin said the plot had apparently reached a fairly advanced stage, but declined to say how close Abdo was to carrying out the attack. Abdo is expected to be arraigned on a variety of federal charges, including terror-related offenses, Thursday night or Friday morning.
"We would have probably been here today giving a different briefing if he had not been stopped," Baldwin said.
The planned attack will force senior military personnel to again confront uncomfortable questions about the degree of Islamic radicalization within its ranks.
Abdo is at least the third Muslim-American soldier suspected of trying to kill his fellow troops since the start of the wars in Afghanistan and Iraq. In 2003, then-Sgt. Hasan Akbar threw a grenade into a tent in Kuwait, killing a pair of American soldiers. Six years later, Maj. Nidal Hasan was charged with opening fire on a crowd of troops at Fort Hood, killing 13 people-including 12 soldiers-in the worst act of military-on-military violence in U.S. history.
Akbar was sentenced to death, and military prosecutors recently said Hassan would face the death penalty if convicted. A civilian Muslim-American convert named Abdulhakim Mujahid Muhammad was sentenced to life in prison earlier this month for a separate 2009 attack on a military recruiting center in Little Rock, Ark., which killed one soldier and badly wounded a second.
Hundreds of Muslim-American soldiers have served in Iraq and Afghanistan, but the attacks have highlighted a worrisome dynamic in which a tiny fraction of those troops have become radicalized-either by their own changing feelings toward the United States or through exposure to extremist Islamist clerics-to such a degree that they were willing to kill U.S. troops.
In the aftermath of the 2009 Fort Hood rampage, lawmakers from both parties accused the Army of turning a blind eye to the extent of the Islamic extremism within its ranks because top officers didn't want to alienate other Muslim-American troops or suggest all such personnel were somehow suspect.
Critics noted that colleagues of Hasan's at the Walter Reed Army Medical Center, where he had done his residency and served as a psychiatrist before being transferred to Fort Hood, said the alleged shooter expressed fervently Islamist views and deep opposition to the wars in Iraq and Afghanistan. In at least one case, Hasan gave a public presentation titled "Is the War on Terrorism a War on Islam: An Islamic Perspective," which was interrupted after participants complained that he appeared to be encouraging terror attacks against the United States.
Investigators also uncovered evidence that Hasan had been in regular contact with radical cleric Anwar al-Awlaki, a U.S. citizen with ties to al-Qaida who is thought to live somewhere in Yemen. The Obama administration has authorized the CIA or the military's special operations forces to kill Awlaki when located.
In the new case, military and civilian officials cautioned that Abdo's motivations remained unclear. He had received conscientious objector status to avoid serving in Afghanistan, but military authorities rescinded his release after they allegedly discovered child pornography on his computer.
Abdo had been slated to face a general court martial, and one military official at the Pentagon suggested that Thursday's planned attack could have been meant as revenge for the trial. Law enforcement officials in Killeen, by contrast, say that Abdo appears to have been willing-and nearly ready-to commit an act of Islamist terror.
Investigators believe Abdo was working alone, but they are probing his movements in recent months to see if the suspect met with anyone suspicious or communicated electronically with Awlaki or other extremist clerics. Regardless of where the investigation leads, the military-which had hoped to put the difficult questions raised by the Hasan case behind it-will again be forced to confront the specter of an enemy within.