Authorities in southern Louisiana on Wednesday arrested a suspect in a spate of fires that have burned three black churches in St. Landry Parish since last month, according to federal prosecutors.

“A suspect has been identified in connection with the three church burnings in Opelousas, Louisiana, and is in state custody,” said U.S. Attorney David C. Joseph in a statement describing “despicable acts” of arson that have frightened black communities and prompted worry they were racially motivated crimes.

The Louisiana State Fire Marshal’s Office, which has led the investigation into the blazes, declined to comment on the arrest. Multiple local media outlets in Louisiana have identified the suspect as a 21-year-old man who is the son of a St. Landry Parish deputy. Authorities will release more information on Thursday morning.

“I’m very proud of the investigative effort that has led to this arrest. I’m prayerful that we can close this horrific chapter and begin to heal,” Rep. Clay Higgins (R-La.) said in a statement sent to KATC.

When Mount Pleasant Baptist Church in Opelousas, La., caught fire on April 4, consuming the church’s interior, it was the third predominantly black church to burn down in St. Landry Parish in the span of 10 days, setting local residents on edge.

On March 26, flames reduced St. Mary Baptist Church in Port Barre to just a few walls and piles of rubble. And on April 2, a blaze struck the Greater Union Baptist Church in Opelousas.

Authorities still have not determined a motive and have declined to tell residents whether they believe race was a factor in the crimes, according to The Advocate.

On Sunday, State Fire Marshal H. “Butch” Browning told worshipers at Mount Pleasant that about 200 state investigators were working the case alongside federal investigators.

Butch has said all three fires were suspicious. “If you’re going to turn to a house of God, turn to it for resurrection,” he said.

A fourth fire on March 31 was reported more than 200 miles away at the predominantly white Vivian United Pentecostal Church in Caddo Parish, La., but authorities have not established a link to the St. Landry incidents.

For some, the recent fires recall a dark history of attacks and threats against black churches in the South. During Reconstruction and the civil rights movement, black churches were targeted with fires, bombings and threats.

In 2015, a white-supremacist gunman opened fire on a prayer group at the Emanuel AME Church in Charleston, S.C., killing nine black people. Nearly 200 years before, Emanuel AME’s predecessor had been burned down in 1822 by Charleston’s white leaders, who feared an insurrection by the city’s enslaved residents.

A man in Mississippi pleaded guilty to arson last month for setting fire to a black church in 2016. He had attempted to disguise the arson as a hate crime.

As authorities investigated the St. Landry fires, churches’ leaders were resilient, though baffled by the attacks.

“My church has a lot of history,” the Rev. Gerald Toussaint of Mount Pleasant Baptist Church told The Daily Advertiser, noting that it was more than 140 years old. “I don’t understand it. What could make a person do that to a church?”

Greater Union had served worshipers for more than 100 years, according to Pastor Harry Richard, whose grandfather helped found the church.

“He left a legacy for me and I was trying to fulfill that to the best of my ability,” he told CBS News.

Toussaint told ABC News that “the church is not that building. The church is the people."

“If we stay together as a congregation, the church is alive and well,” he said. “We can rebuild the building as long as we stay together.”

Michael Brice-Saddler contributed to this story.

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