The fire broke out just before 7 p.m. Wednesday at the New Jerusalem Missionary Baptist Church located at Pine Street and Vandever Avenue.
Upon arrival, officials said the one-story church was engulfed in flames and a second alarm was struck.
Longtime church pastor C. Eugene Brock describes the moment he got the call.
"Somebody called me and said 'the church is on fire.' And I said 'You're joking, this was last week! Two weeks ago we had a fire, you just get the news?' 'No, the church is on fire now,'" Brock said.
The fire was brought under control at 7:49 p.m., officials said.
Officials tell Action News there was nothing they could do to salvage the building, and their main focus was on keeping the fire from spreading to nearby homes.
Still, six adjacent homes were damaged.
The injured fireman was taken to Christiana Hospital for a back injury where he was treated and released.
The FBI and agents from the Bureau of Alcohol, Tobacco, Firearms and Explosives were brought in to assist city and state officials in determining the cause of the fire.
Battalion Chief Timothy Perkins with the Wilmington Fire Department said he could not confirm if the fire was being considered suspicious.
Officials said agents are brought in any time there is a church fire to determine if it was a hate crime.
Two weeks ago, officials said, a fire broke out in the basement of the church. The cause of that fire is also unknown.
"We were cleaning it out to get ready to renovate the whole church. Yesterday they were here clearing stuff out and it was looking good," Brock said.
Mary Dungee said her father, the late Rev. Alarchia Jackson, built the church back in the '60s.
"I'm really brokenhearted because my dad built that church, and so now it's gone," said Dungee.
Church members said they were devastated thinking they were going to be able to save the building after the first fire.
"For them to come and see these people, their homes are all messed up and the church is gone," said Dungee. "It's heartbreaking, it really is, but I trust in God."