CHATTANOOGA, United States (AFP) - The death toll in the mass shooting of US military personnel in Tennessee rose to five on Saturday as investigators pursued the motive behind the rampage.
In a brief statement, the US Navy said a petty officer succumbed overnight to wounds he sustained in Thursday's attack on two military centres in Chattanooga.
The Navy did not identify the sailor, but relatives named him as Petty Officer Randall Smith, a father of three daughters who had recently re-enlisted and transferred to Chattanooga.
"It's hard to understand how somebody can hurt somebody that's serving for you, for your freedom, for your safety," his step-grandmother Darlene Proxmire told WANE television in Indiana.
Four Marines also died in the attack - which authorities are treating as "an act of terrorism" - before the gunman, Mohammad Youssuf Abdulazeez, 24, a naturalised US citizen born in Kuwait, died in a shootout with police.
The FBI has asked foreign intelligence agencies to help trace Abdulazeez's movements and activities abroad, and analysts will be tracing his activity on social media, officials said.
But it warned against jumping to conclusions, after Michael McCaul, chairman of the House of Representatives homeland security committee, branded the attack "an ISIS-inspired attack."
"At this time, we have no indication that he was inspired by or directed by anyone other than himself," FBI special agent Ed Reinhold said, referring to Abdulazeez.
"We obviously want to know what his thoughts were and who else he was associating with."
The shooting has jarred Chattanooga, a city of 168,000, where the Islamic Society of Greater Chattanooga condemned the attack and cancelled its end-of-Ramadan Eid al-Fitr celebration out of respect for the victims.
DETAILS EMERGE
Going into the weekend, more details about Abdulazeez - a University of Tennessee engineering graduate and mixed martial arts enthusiast who grew up in a middle-class neighbourhood - slowly emerged.
Investigators were looking at Abdulazeez's foreign travel, with a reported trip to Jordan last year of particular interest.
There was evidence, however, that he came from a troubled family.
Divorce papers filed by his mother alleged that his father beat his wife and five children.
The father was also reportedly investigated for ties to a terrorist group, but ultimately was cleared.
Abdulazeez's only known brush with the law was in April, when he was arrested for driving under the influence.
He briefly worked at a nuclear power plant in Ohio in May 2013, but was fired after failing to meet minimum employment requirements, a spokeswoman for Perry Nuclear Power Plant operator FirstEnergy said.
In Washington, Defence Secretary Ashton Carter has asked for recommendations on how to "ensure the safety of service members and civilians at military installations," Pentagon spokesman Peter Cook said.
But state governors in Louisiana and Oklahoma opted to immediately sign orders that would allow US military personnel to carry firearms at recruiting centres, which often are situated in civilian shopping malls.
