Meanwhile, federal Bureau of Alcohol, Tobacco, Firearms and Explosives investigators spent Tuesday collecting evidence from a Wilson County home where a package exploded the day before, killing Jon Setzer, 74, and seriously injuring Marion Setzer, 72, the (Nashville) Tennessean reported.
After eliminating all accidental causes in Monday's blast, the Tennessee Bureau of Investigation offered an $8,000 reward for information that results in an arrest and conviction in the case.
Agents would not discuss exactly where the blast occurred, or details about the device, including how it was delivered to the home, the Tennessean said.
"We do not respond to this kind of event every day," said Dewey Woody of the state fire marshal's bomb and arson division. "But when we do, we have to take it like we do every day and process it very slowly."
WZTV, Nashville, said Setzer's friends indicated his health had declined recently.
Records indicated Jon Setzer was a retired lawyer.
Setzer's former law partner, George Cate Jr., told WZTV he was shocked to learn of Setzer's death. He said his former partner was optimistic and a dedicated lawyer.
The Tennessean said his home was near McClain Christian Academy, which relocated its main campus to a church in Lebanon because of the explosion.