Investigators believe a pair of men in their 20s or 30s, likely "bosom buddies," are responsible for a string of church fires in rural Alabama, as authorities confirmed the latest blaze at a Baptist church was the 10th case of arson.

The latest fire severely damaged Beaverton Freewill Baptist Church in northwest Alabama, near the Mississippi line. The white, wood-frame church sat about 150 yards off a two-lane county road and had an alarm system that alerted officials to the blaze.

"It's definitely arson," state fire marshal spokesman Ragan Ingram said Sunday.

Fire marshals are investigating whether the Saturday afternoon blaze was linked to the other nine this month, which all were set in the pre-dawn hours. Last week, Gov. Bob Riley said the nine earlier church fires appear linked.

A federal investigator said witness reports and behavioral profilers led authorities to believe that two white men were responsible for the fires. Witnesses said they saw two men in a sport utility vehicle near a number of the fires.

"They're not youths or teens. It's probably someone in their 20s or 30s. We believe they're pretty much inseparable. They're something like bosom buddies," said Eric Kehn, a spokesman for the federal Alcohol, Tobacco, Firearms and Explosives agency.

Evidence from one of the earlier fires indicates the perpetrators may have been briefly trapped inside the building and may have been hurt, said Jim Cavanaugh, ATF regional director.

Investigators have said they don't know a motive, but there is no racial pattern. Five of the churches had white congregations and five black. All were Baptist, the dominant faith in the region, and mostly in isolated country settings.