Pastor Frank Treme didn’t think his church could possibly be in danger when he got a call Thursday night from a congregation member who saw a posting on Facebook about a fire on Sullivan Road in Slidell.

But when he drove by the Bayou Baptist Church building, which volunteers had rebuilt after Hurricane Katrina, he saw the firetrucks.

St. Tammany Fire Protection District No. 1 got the call at 10:30 p.m. and responded within four minutes, spokesman Chad Duffaut said Friday. The fire was brought under control an hour and 18 minutes later, with 16 units and 34 firefighters responding, he said.

He estimated that 50 percent of the building had sustained heavy fire damage, with the rest of it badly singed by the smoke.

Duffaut and Slidell Police Department spokesman Sgt. Daniel Seuzeneau both said there were suspicious elements to the fire. But Seuzeneau said the investigation of its cause is still in its early stages, and it is too soon to say whether it was arson.

Treme, however, is sure the fire was set intentionally. There was evidence that the inside of the church had been vandalized, he said, and items had been carried out, as if there had been an effort to burglarize the building.

“This was not an accident,” he said. “Somebody torched it on purpose.”

Treme said the congregation is waiting to hear from its insurance company about the extent of the damage, but he is doubtful that the building can be renovated.

The congregation will have to decide what to do when more information is available, he said. “They’re just heartbroken right now,” he said.

It will be the second time in 10 years that his congregation has had to rebuild its sanctuary.

“This church withstood Katrina,” member Danny Bryant said. “We had 3 to 4 feet of water in here. We gutted, rebuilt and now to have this happen — it definitely tests your faith.”

The congregation originally was located in the Bayou Liberty area but bought the Sullivan Road property in 1963. Bayou Baptist was aided in its post-Katrina rebuilding by volunteers and donations.

The process took a year, and during the interim, the congregation worshipped at the home of a church member, Treme said.

Treme said he hopes to have services this Sunday on the property, in a gazebo under a large oak tree.

“With the power of the Lord, we’re going to rebuild,” he said.

Follow Sara Pagones on Twitter, @spagonesadvocat.