CHATTANOOGA — It took about two days for the FBI to announce it was investigating the Dec. 2 attack that killed 14 in San Bernardino, California, as an act of terror.

Nearly five months after the killing of five military personnel in Chattanooga, Tennessee, authorities have carefully avoided using the same wording about the attack by a Kuwaiti-born gunman.

As a practical matter, labeling Chattanooga a terror attack would make its victims eligible for the Purple Heart, which if awarded would entitle their survivors to additional payments and benefits.

There’s also a key difference between Chattanooga and San Bernardino in terms of how publicly authorities have announced investigative details and drawn conclusions, said former federal prosecutor David S. Weinstein: the ramped-up visibility of extremism after the deadly attacks in Paris blamed on adherents to the Islamic State extremist group.

“What has changed is U.S. and world perception about terrorists and how the U.S. is combating terrorism,” he said. “That national pulse about terrorism is high.”

At a news conference the day of the Chattanooga shooting, then-U.S. Attorney Bill Killian said the shooting was being investigated as an act of terrorism. Minutes later, he backtracked, saying the investigation would determine whether it was terrorism or some other crime.

The closest federal authorities have come since to calling Chattanooga a terror attack was Dec. 6, when President Barack Obama addressed the nation from the Oval Office after San Bernardino. The president noted that as the U.S. has improved in preventing large-scale assaults like those on Sept. 11, 2001, “terrorists turned to less complicated acts of violence like the mass shootings that are all too common in our society.”

Obama then cited both Chattanooga and San Bernardino, as well as the 2009 shootings at Fort Hood, Texas, that killed 13 people and wounded 32 more. The Fort Hood attack, initially called an instance of workplace violence by many authorities, resulted in the murder conviction and death sentence of Nidal Hasan, a former U.S. Army major who said during his court-martial he believed he was defending Taliban leaders from American troops.

Joyce McCants, a spokeswoman for the FBI in Knoxville, Tennessee, which oversees Chattanooga, said Thursday that the bureau is likely to provide an updated statement this week about the July 16 killings by Muhammad Youssef Abdulazeez.

Abdulazeez, 24, was fatally shot by police after opening fire at a military recruiting center and then driving to a reserve center, where he killed four Marines and a sailor.

Within hours of the shooting, Attorney General Loretta Lynch issued a statement describing a “national security investigation” — which immediately suggested the possibility of terrorism. No such statement came from the Justice Department on the night of the San Bernardino attacks as investigators worked to determine a motive.