Notre Dame Forward Brianna Turner (11) drives past Arianne Whitaker (4) of Chattanooga in the first half of an NCAA college basketball game, Tuesday, Dec. 27, 2016, in Chattanooga, Tenn. (AP Photo/Billy Weeks)
The American flag is lowered to half-staff above the White House in Washington, Tuesday, July 21, 2015, to honor the five U.S. service members who were killed by a gunman in Chattanooga, Tenn., last week. (AP Photo/Andrew Harnik)
An FBI investigator investigates the scene of a shooting outside a military recruiting center in Chattanooga, Tennessee, on July 17, 2015. (Associated Press) **FILE**
A former Marine who manages a Chattanooga, Tennessee, restaurant honored the four troops killed by a gunman in a July 16 attack on two nearby military facilities by setting a table as a memorial. (WTVC)
A car tangled in fencing sits parked just inside the gate at the Naval Operational Support Center and Marine Reserve Center where a gunman opened fire Thursday killing four U.S. Marines Friday, July 17, 2015, in Chattanooga, Tenn. (AP Photo/John Bazemore)
Thomas J. Sullivan, 40, of Springfield, Massachusetts, was killed in an apparent terror attack on Thursday, July, 16, 2015, in Chattanooga, Tennessee. Facebook photo.
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. (Associated Press)
In this image made from video and released by WRCB-TV, authorities work an active shooting scene on amincola highway near the Naval Reserve Center, in Chattanooga, Tenn. on Thursday, July 16, 2015. Chattanooga Mayor Andy Berke says police are pursuing an active shooter after reports of a shooting at the military reserve center. (WRCB-TV via AP)
Defense Secretary Ashton Carter ordered a review of base security procedures Friday afternoon, just one day after four Marines were killed by a gunman in Chattanooga, Tenn. (Associated Press)
UAW Secretary-Treasurer Gary Casteel (right) stands with Volkswagen employees at a news conference Thursday in Chattanooga, Tenn., at which Mr. Casteel announced the formation of a new local of the United Auto Workers' union, with the blessing of the German automaker's officials. (Associated Press)