CONCORD (CBS SF) — A homeless man was arrested Monday after firefighters responded to a second blaze in less than a week at Concord’s Christ Community Church of the Nazarene.

Concord police said they believe the man attempted to light three fires at the complex late Sunday night-early Monday morning. They have yet to say if he was also a suspect in a fire that erupted at the church last Thursday.

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The fire, which was reported after midnight, was located in an entirely different section of the complex which appears to house a worship center and offices.

Arriving firefighters discovered heavy smoke and fire coming from the inside of the building. The blaze did significant damage to the worship area, damaging a large cross and burning worship books.

The smoky fire was contained several hours later. No injuries were reported.

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Firefighters initially responded at 5:32 a.m. last Thursday to a fire reported at the church and extinguished it about 40 minutes later.

The blaze caused the roof to collapse and the second floor to collapse onto the first, so investigators could not enter the building until Friday after heavy construction equipment was brought in to make sure the structure would not collapse further, fire district spokesman Steve Hill said.

“It’s not an easy job digging through all those layers of rubble,” Hill said, adding that the district also brought out a cadaver dog to make sure no one was inside the building at the time of the fire.

According to fire investigators, the blaze started in the crawlspace underneath the church near sleeping materials and other items that appeared to belong to someone who was temporarily sheltering under the structure unauthorized.

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Investigators, however, weren’t able to determine whether the fire was intentionally set or whether it was an accident.