The family of the man who authorities say killed four Marines and sailor in Chattanooga said in a statement that their son suffered from depression and was not the son they knew.

"There are no words to describe our shock, horror, and grief," said the statement, provided Saturday to the Associated Press by a lawyer representing the family of Muhammad Youssef Abdulazeez. "The person who committed this horrible crime was not the son we knew and loved. For many years, our son suffered from depression. It grieves us beyond belief to know that his pain found its expression in this heinous act of violence."

"We understand there are many legitimate questions that need to be answered," the statement said. "Having said this, now is the time to reflect on the victims and their families, and we feel it would be inappropriate to say anything more other than that we are truly sorry for their loss."

The family added that they are cooperating with the investigation.

In Chattanooga, a city that prides itself on strong ties between people of different faiths, some Muslims feared the community's perception of them had changed after the shooting rampage Thursday.

Mohsin Ali, a member of the Islamic Society of Greater Chattanooga, said he hoped the local community didn't dissolve into turmoil the way others have in the region over the building of mosques and other matters. Peaceful coexistence has largely prevailed here.

"We, our kids, feel 100 percent American and Chattanoogan," said the Pakistani-born Ali, who is a child psychiatrist. "Now they are wondering if that is how people still look at them."

As FBI agents served a warrant on the Abdulazeez home Thursday, two women wearing Islamic head coverings were seen being led away in handcuffs. But FBI agent Jason Pack said Saturday that no arrests have been made in the case.

Authorities are looking into the shooting as a terrorism investigation and whether Abdulazeez was inspired or directed by any terrorist organization. They still don't know what motived Abdulazeez.

The president of the Islamic Society of Greater Chattanooga said Abdulazeez's father told him he felt blindsided and did not see any recent changes in his son.

"He told me that he had never seen it coming, and did not see any signs from his son that he would be that way and do something like that," Bassam Issa said.

Meanwhile, governors in at least a half-dozen states ordered Guardsmen to be armed, and Florida Gov. Rick Scott moved his state's Guard recruiters from storefronts in urban areas to armories.

Ali said immigrants such as himself owe a debt of gratitude to America and the armed forces protect it, because they often know firsthand what it means to live in countries without personal freedoms or the rule of law. Near the end of the service Friday night, at Ali's urging, dozens of Muslims received a standing ovation as they stood in support of their city and in allegiance to their nation.

It was a remarkable show of togetherness in a region where relations have sometimes been tense since the terror attacks of Sept. 11, 2001.

Still, the events of the last few days have left some on edge, particularly the young. The end of Ramadan is usually a time for celebration, but events at the Islamic Center were canceled after the shootings. A sign on the door Friday encouraged visitors to go to the memorial service instead.

Khadija Aslam, 15, didn't wear her head covering in the car while riding to prayer services after the shootings for fear of attracting attention, and 15-year-old Zoha Ahmad said her family is worried about the possibility of vandalism at their home.

"A lot of people know we live there and that we're Muslims," she said.

Ali said he plans to offer group counseling for concerned members of the Islamic community at his home, and that might help ease concerns. But, he isn't sure.

"We'll see," said Ali.