The strip mall where a gunman opened fire outside an Armed Forces Career Center in Chattanooga. (@ASpiratoNC9/Twitter)
Police officers enter the Armed Forces Career Center through a bullet-riddled door after a gunman opened fire on the building Thursday, July 16, 2015, in Chattanooga, Tenn. (AP)
The doors of the military recruiting center that was targeted. (April Grimmett)
Plastic cups mark evidence outside the Armed Forces Career Center after a gunman open fire on the building Thursday, July 16, 2015, in Chattanooga, Tenn. (AP)
The military recruiting center targeted by the gunman. (@ASpiratoNC9/Twitter)
Law enforcement on the Du Pont Parkway near the shooting scene. (@peterjguarneiri/Twitter)
Law enforcement gathered on the Amnicola Highway. (jessica_adams94/Instagram)
People lining up to donate blood following the shooting. (@boyd_gabrielle/Twitter)
A police photo of shooting suspect Mohammad Youssduf Adbulazeer following an arrest for suspected DUI on April 20, 2015. (ABC News)
A high school yearbook photo of suspected shooter Muhammad Youssef Abdulazeez of Hixson, Tennessee. (ABC News)
In this frame from video, law enforcement officers detain a woman as they surround a house in Hixson, Tenn., Thursday, July 16, 2015. (AP)
A police officer investigates outside the Armed Forces Career Center after a gunman opened fire on the building Thursday, July 16, 2015, in Chattanooga, Tenn. (AP)
Members of a SWAT team sit on the back of a vehicle in Hixson, Tenn., Thursday, July 16, 2015. (AP)
In this frame from video, law enforcement officers detain a woman as they surround a house in Hixson, Tenn., Thursday, July 16, 2015. (AP)
President Barack Obama, left, sits with FBI Director James Comey, right, before speaking to members of the media in the Oval Office, Thursday, July 16, 2015. (AP)
At least four Marines were killed and a soldier and a police officer were wounded in shootings at two military facilities Thursday in Tennessee. The shooter also was killed.