An attorney at the firm who left the office just before the blast said employees told him they saw a man trying to drive his vehicle into the building and locked the doors. Investigators were searching the 71-year-old suspect's house and thought there might be a bomb in his vehicle at the scene, Georgia Bureau of Investigation spokesman John Bankhead said. The suspect's name was not immediately released.
Witnesses said windows were blown out at McCamy, Phillips, Tuggle & Fordham in Dalton, 26 miles southeast of Chattanooga, Tenn.
The building was still on fire more than four hours after the initial explosion, and officials were waiting for firefighters to get the blaze under control before searching the truck and the building, Bankhead said.
"Our primary focus right now is just getting the fire out because it's a crime scene, and we obviously want to get as much evidence as possible out of there," Frazier said.
Two of the injured were treated at a hospital and released, one was admitted and a fourth was taken to a burn center.
Attorney Robert Smalley, a lawyer at the firm, left 15 to 20 minutes before the blast but turned back when he received phone calls about it.
He said those injured were his assistant, Teresa Stinnett, attorney Jim Phillips and two clients. Phillips was taken to the burn center.
"We'll take today with our families and try to regroup," he said "Our thoughts right now are with the injured and their families."
He said Stinnett has a shoulder injury but is going to be OK. Smalley said he was able to visit with Phillips after the explosion.
The eight-lawyer firm, founded in 1932, works out of a two-story, colonial-style house. Police cordoned off the block and shut down a post office near the law firm, which specializes in personal injury and wrongful death cases, according to its Web site.
Students at an elementary school across the street were evacuated to a nearby church.
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