OPELOUSAS, La. — The suspect in a string of fires that destroyed three black churches in rural Louisiana is the white son of a sheriff’s deputy whose father helped arrange for his arrest, authorities said Thursday.

Holden Matthews, 21, was jailed without bail on arson charges in connection with the blazes in and around Opelousas, a city of 16,000 where the flame-gutted remains of the buildings evoked memories of civil rights era violence.

Louisiana Fire Marshal Butch Browning offered no motive for the fires. He and other officials stopped short of calling them hate crimes. Eric Rommal, the agent in charge of the New Orleans FBI office, said investigators were still looking into whether the fires were “bias motivated.”

Browning said there were no indications that anyone else was involved and the danger to churches was over.

“This community is safe again,” he told a news conference. “We are extremely, unequivocally confident that we have the person who is responsible for these tragic crimes.”

The Rev. Harry Richard, pastor of Greater Union Baptist Church, which was destroyed, said the arrest put him at ease.