An image of Cambridge’s Faith Lutheran Church after an April 9 fire. (Photo FBI)

The fire at Cambridge’s Faith Lutheran Church last week is considered suspicious and officials are seeking the public’s help in investigating.

“We are asking anyone with information on this fire, or who made observations in the area of the church that Sunday evening, to share it with investigators,” said acting fire chief Tom Cahill.

Cahill announced the suspicions Tuesday in a statement with Cambridge police commissioner Christine Elow, state fire marshal Peter Ostroskey, FBI Boston special agent in charge Joseph Bonavolonta and James M. Ferguson, special agent in charge with the Bureau of Alcohol, Tobacco, Firearms and Explosives in Boston.

The church’s Rev. Robin Lutjohann said that he was learning of the suspicions of arson with everyone else – including other church members.

Another view inside the burned Faith Lutheran Church in Cambridge. (Photo: FBI)

“As far as I know, this is news to the church in general. We’re all hearing the announcement of arson all at the same time,” Lutjohann said.

There hadn’t even been rumors that had reached him. “I don’t want to give in to any kind of speculation. It’s not my go-to to assume some nefarious action on anybody’s part,” Lutjohann said. He trusted investigators to “find out what they will find out, and I hope they have all the resources and information they need to do that.”

Faith Lutheran Church, at 311 Broadway in The Port neighborhood of Cambridge, burned April 9. It was a six-alarm fire on Easter Sunday that lasted some four hours, hollowing out a three-story, stucco-walled church built by working-class Swedish immigrants in 1909. 

The building’s final use before the 5:30 p.m. fire was a 12:30 to 4:30 p.m. service by an Eritrean congregation from Boston. No congregant or visitor was in the building when the fire broke out, officials said.

Fighting the fire took crews from a dozen communities. On April 11, safety concerns demanded removal of the church’s steeple.

Investigators lingered at the scene into the week that followed. “The joint investigation into the fire began at the scene as suppression efforts were underway and continues,” according to the FBI. The Cambridge fire and police department, state police in the State Fire Marshal’s Office and federal investigators are involved, the agency said.

“No piece of information is too small to share. We are keenly aware that any place of worship is a cornerstone of the community, and we want to reassure residents that we’re approaching this case with the seriousness and gravity that it deserves,”

Tips can be made to the FBI’s toll-free tip line at 1-800-CALL-FBI (1-800-225-5324) or online at tips.fbi.gov. Investigators are also asking anyone with photographs or videos of the church the day before the fire, the day of the fire and during the firefighting operations, to submit them to fbi.gov/cambridgechurchfire.