Authorities denounced the torching of three historically black churches as "evil acts" at a press conference Thursday, following the arrest of a sheriff's deputy's son. The three churches burned in one Louisiana Parish in just 10 days, devastating to the St. Landry Parish community.

Authorities said Thursday all three fires were intentionally set, and all have been linked to one suspect — 21-year-old Holden Matthews. The suspect's father is Deputy Roy Matthews.

Matthews' social media shows he had an interest in black metal music and is the lead singer for a band called Vodka Vultures. Records show Matthews lives in Saint Landry Parish, where the churches burned just a few miles apart.

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Louisiana fire marshal H. "Butch" Browning said investigators have not developed a motive. However, he said investigators are looking into a possible link to Matthews' interest in black metal, an extreme subgenre of heavy metal, and its association with church burnings. The black metal scene was associated with Christian church burnings in Norway in the 1990s, and a smaller subset of black metal bands espouse neo-Nazi beliefs, reports the Associated Press. In 1994, Norwegian black metal musician Varg Vikernes was sentenced to 21 years in prison for manslaughter in the stabbing death of a fellow band member and for arson attacks on three churches.

Vikernes, a far-right figure and alleged sympathizer of Norwegian mass murderer Anders Behring Breivik, was arrested in 2013 for an alleged terrorist plot. Matthews posted a comment on social media about a movie's portrayal of Vikernes, reports the AP.

The FBI is investigating whether the Louisiana church arsons were bias-motivated, officials said.

Browning said the fires completely destroyed the buildings, structures that were more than 100 years old, where he said "generations" of families had been raised.

"Though the spirit is still strong, the landmarks have been destroyed," Browning said.

Matthew Holden, 21, is suspected of torching three historically black Louisiana churches WWL-TV

Matthews was charged Thursday morning with three counts of simple arson of a religious building. The maximum penalty for each counts is 15 years in prison.

"Nobody should ever fear for their safety in a house of worship, or fear their church will be destroyed," Louisiana governor John Bel Edwards said. "I don't know what this young man's motive was. I don't know what was in his heart. But I can say it cannot be justified or rationalized. Let me be clear — these were evil acts."

The churches were empty at the time of each fire and no one was hurt.

Earlier this week, the NAACP said the church burnings were "domestic terrorism," targeting people because of their skin color and faith.

Browning said investigators quickly honed in on Holden Matthews using technology, video surveillance and evidence collected at the scene. He also said the pastors aided, calling them "very unique criminal investigators."

Roy Matthews had no knowledge of his son's alleged crimes, said St. Landry Parish Sheriff Bobby Guidroz, who employs the father. Guidroz said the elder Matthews "broke down" when he called him into his office to inform him of the arrest.

Guidroz said the elder Matthews "helped facilitate" his son's arrest by getting him away from his home to an area where he could be safely approached by deputies. Holden Matthews was arrested without incident.

Harry Richard — pastor of Greater Union Baptist Church, the site of the second fire — said he's relieved about the arrest.

"This takes a lot of the pressure off us," Richard said.

Editor's note: A previous version of this story stated that the suspect's father, Deputy Roy Matthews, turned his son in. In a press conference Thursday morning, St. Landry Parish Sheriff Bobby Guidroz said that report was incorrect. Sheriff Guidroz said the suspect's father "helped facilitate the arrest, he got the suspect away from home" and had "no knowledge" of his son's activities.