Members of the task force also are checking out fires at churches in other states to make sure the blazes don't fit into a pattern. So far, they say, no blazes linked to the Alabama cases have surfaced elsewhere.
But when someone tried to set fire to a church in south Mississippi last week, authorities there passed along details on the crime to agents investigating the 10 arsons in Alabama.
The same thing happened after a fire at an old church in Georgia, according to Ed Paulk, an assistant state fire marshal in Alabama.
"Everything in the Southeast right now is kind of coordinated with this," said Paulk.
"As we have church fires in surrounding states, in order not to overlook anything, we are communicating with those states to make sure what is happening here is not being replicated anywhere else," Paulk said in an interview Thursday.
No fires linked to the Alabama arsons have occurred since Feb. 11, and no arrests have been made. But the head of the fire task force said an intensive investigation continues, with new agents being brought in and more than 700 leads under review.
"It's still solvable," said Jim Cavanaugh, the regional head of the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives. Authorities have located one of several vehicles sought after the initial fires, and subpoenas have been issued, but details have not been made public.
Investigators also are checking on whether other fires outside Alabama fit the pattern seen in the arson cases: Isolated Baptist churches set aflame by someone who tried to start a fire in the pulpit area.
A fire that authorities described as suspected arson hit Spring Beulah Church of Christ in McComb, Miss., last Sunday, causing minor damage to the fellowship hall. It was the second fire to hit the church since 2004, and investigators said it wasn't related to the Alabama cases.
In Georgia, Insurance Commissioner John Oxendine said the old Harmony Grove Baptist Church in Roswell sustained $50,000 in damage in a fire Monday, but there was no apparent link to the Alabama cases.
"It definitely was arson," he said. "It was a former church that was unoccupied."
Paulk said the Alabama task force asked surrounding states to inform them of suspicious church fires.
"We're just making sure there is nothing we are missing," said Paulk. "It's just being proactive."