The city's entire fire department — about 35 people — responded to the call at the Anglican Church of St. John the Baptist Saturday morning.
City spokesperson Mychèle Poitras said the fire started under a deck attached to the church.
"Right now, it's suspicious, mainly due to the fact that it started outside on an exterior wall," she said. "And let's just remember that two weeks ago, another building located just beside the church also burnt down."
Poitras said the earlier fire is now also under review by the police.
'Oh, it's awful'
The church was built in 1873 and classified as a historical site in 1991. The building was empty at the time of the fire.
Christine Goon, who has been a member of the congregation for more than 30 years, said there are about 50 families who belong to St. John the Baptist in Edmundston.
She's still having a hard time understanding what happened.
"Oh it's awful. For me, it's really a big shock," she said.
Goon said St. John the Baptist was formed by merging the dwindling United and Anglican congregations Edmundston. She said the church has helped many people in the community.
"It was a very pretty church and now it's gone, sadly," Poitras said.
Poitras and Goon both urge anyone with information about either fire to contact the police.