Holden Matthews, 21, was charged with three counts of simple arson on religious buildings. Picture: St. Landry Parish Jail/Handout via Reuters

Chicago - The white son of a Louisiana police officer has been arrested and accused of burning down historically black churches in the southern US state, authorities announced Thursday.

Holden Matthews is charged with three counts of arson on a religious building for allegedly burning down three rural churches over a 10-day period beginning in late March. 

Each charge carries a maximum penalty of 15 years in prison.

Authorities said they were not ready to discuss the motive for the attacks, but a federal hate crimes investigation was ongoing. 

"I don't know what this young man's motive was... but I can say it cannot be justified or rationalised. These were evil acts," Louisiana Governor John Bel Edwards said at a news conference. 

"It has been especially painful because it reminds us of a very dark past of intimidation and fear."

The 21-year-old is allegedly associated with a type of music known as "black metal" which promotes church burnings, authorities said.

In extreme cases, those who associate with the musical genre have espoused white supremacist ideologies, according to The Daily Beast website and the anti-hate group ADL. 

The sheriff in St Landry Parish where the church attacks occurred said the arrested suspect was the son of one of his deputies, Roy Matthews. 

"He knew nothing about his son's activity," Sheriff Bobby Guidroz said, adding that the deputy "broke down" when he was informed. 

"He's shocked and hurt, as any father would be," Guidroz said. 

The arson attacks targeted three historically-black churches -- St Mary Baptist Church in the city of Port Barre, Mt Pleasant Baptist Church in Hammond, and Greater Union Baptist Church in Opelousas.