McMurrey declined to describe the device or to comment on reports of similar devices found in two nearby counties, but she said the public was never in danger.
"If there was anything that was dangerous, we would certainly warn the public or our employees," McMurrey said.
The Tyler Morning Telegraph, citing a Smith County sheriff's report, said the device found in Owentown consisted of a beer bottle filled with gasoline and topped with a wick.
Rusk County Sheriff Danny Pirtle told the newspaper that two incendiary devices were found recently in his jurisdiction. He did not immediately respond to a phone message Friday seeking comment.
A fourth device was found March 5 in a mailbox in the main post office in Kilgore, city police Lt. Roman Roberson told The Associated Press. He said it was a beer bottle that contained an unidentified flammable liquid and a wick. He said the top of the bottle was wrapped in paper that had writing on it, but that he didn't know what was written.
The device didn't pose a threat and was passed on to postal inspectors and the Bureau of Alcohol, Tobacco, Firearms and Explosives, Roberson said.
"I'm not sure what the purpose was behind that," Roberson said. "It looked like somebody was just trying to get somebody's attention or get some attention."
ATF spokesman Tom Crowley said his agency responded to the report of the device in Owentown, but that postal inspectors were leading the investigation.