The Saint John Police major crime unit is investigating after what's being called a "suspicious" fire destroyed a church in the city's west side.

The old, wood-framed, white building on Church Avenue West caught fire at around 4 a.m. Friday.

Saint John building inspectors said what's left of the Torch for Truth Tabernacle Church will have to be torn down because it is unsafe.

The former Pentecostal church had been vacant since 2008, following a flood in the basement.

Fire Chief Kevin Clifford said that's where the fire likely started.

"So we go in — it's on the ground level and it's going up the wall. And actually fire debris was falling on the crews when they were inside," Clifford said.

Clifford said two fire crews went inside the church to try and contain the fire, but within 25 minutes the firefighters concluded they could not save the building.

"It was pretty rough. A lot of support beams were destroyed," Clifford said.

He said the crews pulled out of the church and then began trying to stop the fire from spreading to nearby homes. Police had Main Street blocked and officers were re-routing traffic.

One home on Church Avenue was evacuated, but fire crews managed to contain the fire to the church.

Helen Tompkins, the wife of the former pastor of the chuch says the fire was a shame.

"It just was a beautiful sanctuary and it had such wonderful acoustics because there was just so much wood on the ceiling and up the walls," she said.

Tompkins says the original church on the site burned down more than a hundred years ago.

"It burned before they ever got moved into it, and this building, which is on fire today, was built in the late 1800s."