(CNN) -- The two latest fires in a string of church blazes in east Texas have been ruled arson, bringing the total of deliberately-set fires to 10, authorities said Thursday.
Fires destroyed Dover Baptist Church and Clear Spring Missionary Baptist Church on Monday night. The churches are located about three miles apart near Tyler, Texas.
There have been a total of 11 church fires so far this year, said Tom Crowley, special agent from the federal Bureau of Alcohol, Tobacco, Firearms and Explosives' Dallas, Texas, office. One has not been ruled arson.
Included in that total is a January church arson in Temple, Texas. Authorities are not sure whether the Temple fire is related to the other nine, which have been concentrated in an area east of Dallas, more than 150 miles from Temple.
There is no clear theme linking the fires, which have struck churches of different denominations, including Baptist, Methodist and Church of Christ Scientist, on different days of the week and at different times of the day, Crowley has said. While the churches are located in small towns, not all of them are in remote locations, he told CNN.
Authorities believe one person, or perhaps a group of people, are responsible, he said. Crowley told CNN Thursday investigators were still tracking down leads.
"I think maybe I would characterize the mood of our people as perplexed," Randy Daniels, mayor of Athens, Texas, told CNN on Tuesday. Athens, a town of about 12,000 people, has had three of its church set on fire.
He and others spoke of communities on edge. Police patrols have been stepped up near east Texas churches, while in some cases, church members are staying at their churches to protect them or patrolling churches themselves.
In Tyler, Texas, the Tyland Baptist Church was among those set ablaze. Pastor David Mahfood told CNN on Wednesday there was nothing left from the January 16 fire -- "not a Bible, not a hymnal. We've got some bricks. That's it."
At another destroyed church, Russell United Methodist Church in Wills Point, Texas, members are trying to salvage what they can from the ashes.
A large brass cross that hung over the church's choir loft was recently found, church member Kay Crosby told CNN. "It was kind of twisted, but we're going to have it restored," she said Wednesday.