Opelousas, Louisiana CNN  — 

A suspect has been taken into custody in connection with fires at three historically black Louisiana churches in 10 days, a law enforcement official familiar with the investigation and a local elected official told CNN on Wednesday night.

Two law enforcement officials with direct knowledge of the ongoing investigation tell CNN the subject arrested in connection with three church fires in Louisiana is a 21-year-old man from St. Landry Parish. CNN has been provided the name of the subject but is not reporting it until it is announced by authorities.

Meanwhile, authorities said they will announce significant updates in the case at a news conference Thursday at 10 a.m. CT at the St. Landry Parish Sheriff Public Safety Complex in Opelousas.

Louisiana Gov. John Bel Edwards will attend the news conference, his office said.

St. Mary Baptist Church in Port Barre burned on March 26, followed by Greater Union Baptist Church in Opelousas on April 2 and two days later, Mount Pleasant Baptist Church in the same town.

The fires are believed to have been intentionally set, a local elected official said Tuesday.

Officials are also investigating a fourth, smaller fire on March 31 at the predominantly white Vivian United Pentecostal Church in Caddo Parish, more than 200 miles north of St. Landry. The blaze was intentionally set.

The FBI and federal Bureau of Alcohol, Tobacco, Firearms and Explosives are assisting in the investigations.

The NAACP has labeled the fires “domestic terrorism,” adding the “spike in church burnings in Southern states is a reflection of the emboldened racial rhetoric and tension spreading across the country.”

Once a common occurrence

Church burnings were a common occurrence in the Jim Crow era. And fires at black churches – especially those in the South – immediately bring to mind such racist attacks.

“For decades, African-American churches have served as the epicenter of survival and a symbol of hope for many in the African-American community,” NAACP President and CEO Derrick Johnson said. “As a consequence, these houses of faith have historically been the targets of violence.”

Several black churches in the South were burned in 2015 shortly after the mass murder of nine people at the Mother Emanuel African Methodist Episcopal Church in Charleston, South Carolina, t