The Algerian government has said the attackers came from Algeria, Tunisia, Egypt, Mali, Niger, Canada and Mauritania. U.S. and Algerian officials are still trying to confirm the identities of those involved, according to a federal law enforcement official -- and it was unclear whether the terrorist identified as a Canadian was carrying authentic or false identification.

"The level of co-operation between two countries has been good," the official added.

The FBI has additional investigators in Algeria, where there is an established legal attache office, but authorities declined to say how many agents are there or identify their location.

Algerian officials said the attackers drew on the expertise of a driver from Niger who had once worked at the plant. One former hostage, Mohadmed Aziri, told state-run Chinese broadcaster CCTV about militants flooding into the compound, taking it over bit by bit, searching door to door for workers. He also described rescue efforts.

"The experience was too terrible. I heard the sounds of gunshot, bullets hitting doors," he told CCTV. "I heard the governmental forces and terrorists fighting in the distance. Judging from the sounds of gunfire, the fighting was very intense."

The Algerians initially moved in on Thursday after concluding the militants planned to blow up the gas installation and flee to Mali with the foreigners as hostages. The incursion succeeded in freeing some hostages -- but not all -- and several of them died.

Lovelady survived Thursday's raid. And if his family knew him at all, he was likely biding his time, coolly trying to find a way to help himself and others out of the unthinkable predicament they found themselves in.

'We felt in our hearts that he was coming home'

"He wouldn't be the person who is crying and screaming and begging," Erin Lovelady said. And after the initial exhilarating news, the family felt sure he would pull through.

"We all believed, we felt in our hearts that he was coming home," his daughter said.

But then, on Saturday, Algerian special forces backed by helicopter gunships raided the plant for a second time. They finished off the militants but were unable to save the remaining hostages. Militants may have executed them, Mike Lovelady said he'd been told.

The news, Erin Lovelady said, was "devastating."

Mike Lovelady said he's angry with the terrorists who took the compound his brother thought was safe, resulting in the deaths of people who had traveled there merely to make a better living for their families. But he said things maybe could have been different had Algeria allowed U.S. or British special operations forces to take over.

Maybe, Mike Lovelady said, the U.S. Navy SEALs or Britain's Special Air Service commandos could have taken out the militants while sparing the hostages.

"We all feel it could have been handled differently," he said.

However, Algeria's Interior Ministry said security forces were compelled to intervene quickly "to avoid a bloody turning point of events in this extremely dangerous situation." Officials said Monday that had the terrorists succeeded in blowing up the plant, it would have caused death and destruction in a 5-kilometer (3.1 mile) radius.

On Tuesday, U.S. officials reiterated their support for Algerian officials.

"The blame for this tragedy rests with the terrorists who carried it out," White House spokesman Jay Carney said.

As the family awaits the return of Lovelady's body, and more answers about how he died, Mike Lovelady said he's determined not to let his brother's legacy die with him.

He said he intends to press Congress to keep up the fight against terrorism.