By Christina Maxouris, Josh Campbell and Samira Said, CNN

(CNN) -- Fires that consumed three historically black Louisiana churches in 10 days are believed to have been intentionally set, a local elected official said Tuesday.

The official did not provide specifics about the ongoing investigation but told CNN some pastors in the heart of south-central Louisiana's Cajun and Creole country are sleeping in their churches as a precaution against additional fires.

It is still unclear who is responsible for the fires and will likely take investigators time to sift through what evidence remains to determine if the blazes are connected.

As they do, residents and worshippers in St. Landry Parish, where all three fires occurred, are withholding judgment about what may have caused them, even as officials say they contained "suspicious elements" and the episodes evoke recollections of past acts of hate against black churches.

"I feel our district was being targeted because all three of the churches were in our district," Pastor Freddie Jack, the Seventh District Missionary Baptist Association president, told CNN's Don Lemon on Monday.

"At first we thought it might have been an electrical problem, but then when the second church ... burning occurred I realized it was our sister church. ... Then two days later the third occurred so at least (to) me, (it) made me think that we're being targeted."

St. Mary Baptist Church in Port Barre burned on March 26, followed by Greater Union Baptist Church in Opelousas on April 2 and two days later, Mount Pleasant Baptist Church in the same town.

Officials are also investigating a fourth, smaller fire on March 31 at the predominantly white Vivian United Pentecostal Church in Caddo Parish, more than 200 miles north of St. Landry. The blaze was intentionally set.

St. Landry Parish is nearly 42% black. Opelousas is 75% black.

The city's mayor, Julius Alsandor, called the church burnings "hideous."

"The relevance and the impact on the people in the surrounding communities and especially the congregation of each of these churches, it's hurtful and there may be some fear that is being exhibited by those who are a part of the three churches," he said.

Hurt, fear and confusion -- that's all the congregants are left with for now.

"We don't know why, we don't know when, we don't know who," the Rev. Gerald Toussaint of Mount Pleasant Baptist Church told CNN affiliate KATC. "We will let the authorities handle that, but we just know a higher power and a higher authority who can bring this thing to fruition."

'More questions than answers'

In an appeal for the public's help, Gov. John Bel Edwards said he has directed the state fire marshal as well as local and federal authorities to "aggressively investigative" the fires.

"Churches are sacred places, and no one should fear for their safety in their house of worship," he said. "And no one should be concerned that their house of worship would be destroyed."

"Right now, there are more questions than answers, but hopefully the investigation will yield information we can share with the public in short order," the governor said in his State of the State address, according to CNN affiliate KTBS.

The FBI and federal Bureau of Alcohol, Tobacco, Firearms and Explosives are assisting in the investigations. And as they look for answers, congregants wait.

"Something is not right, something isn't right, but God has the last word," Ethel Thomas, a member of Mount Pleasant, told KATC. "We're going to keep on keeping on."

Thomas told the news station, "It was heartbreaking, I wanted to cry, but I say I'll hold it in.

"I had cried so much already when they called to let me know that our church was burned. I didn't know what else to do, I just said, 'Lord you're in control.' "

NAACP labels the fires "domestic terrorism'

State Fire Marshal H. "Butch" Browning said in a statement there is "clearly something happening" in the community.

"We believe these three fires are suspicious," Browning said. "We are falling short of talking about what caused the fires, falling short of saying they are related, however cognizant that there is a problem and no coincidence that there are three fires."

The NAACP labeled the fires "domestic terrorism," adding the "spike in church burnings in Southern states is a reflection of the emboldened racial rhetoric and tension spreading across the country."

The American Civil Liberties Union called the events "deeply disturbing."

But Jack said it's just too early for conclusions.

"I can't say for one reason or another that the actual burning was a racist act or a hate crime until we can determine who caused them, who's behind them. I don't think that we can rightfully or truthfully say it was either or," he told Lemon. "We need the facts before we can generate thought that's concerning what it was."

And the facts may take a while, because most of the evidence is likely gone.

"Investigating a fire is a very lengthy process," Browning said. "It's one of the most complicated and unconventional crime scenes you'll ever enter because most of the evidence is burned away."

"The problem with arson investigations is the same as bomb investigations: The evidence gets destroyed." CNN law enforcement analyst James Gagliano said. "That's going to be the issue. You've got to go back and piece this together when a lot of the evidence would have been burned up in the fire."

Authorities are reviewing a long list of clues.

"Similar type of accelerant, any type of incendiary device that could have possibly been planted there, and then link in the houses, what things could be found at what crime scene that could be linked to another, find out if there's a pattern and if there's somebody here who's a serial arsonist," Gagliano said.

About 100 federal, state and local investigators are on the case, Louisiana Fire Marshal's Office spokeswoman Ashley Rodrigue said.

'These houses of faith have historically been the targets of violence'

Church burnings were a common occurrence in the Jim Crow era. And fires at black churches -- especially those in the South -- immediately bring to mind such racist attacks.

"For decades, African-American churches have served as the epicenter of survival and a symbol of hope for many in the African-American community," NAACP President and CEO Derrick Johnson said. "As a consequence, these houses of faith have historically been the targets of violence."

Several black churches in the South were burned in 2015 shortly after the mass murder of nine people at the Emanuel African Methodist Episcopal Church in Charleston, South Carolina, though it is unclear if those fires were racially motivated.

According to the latest data from the National Fire Protection Association, fires within religious and funeral properties have been on the decline for decades. Between 2007 and 2011, 16% were ruled intentional, according to the association.