Authorities in southern Louisiana are investigating a string of "suspicious" fires at three African American churches in recent days.

During a news conference Thursday, Fire Marshal H. "Butch" Browning said it wasn't clear whether the fires in St. Landry Parish are connected but described them as "suspicious."

Browning's spokeswoman, Ashley Rodrigue, says all three churches have African American congregations.

Browning says the ATF and the FBI are also involved in the investigation.

The first fire occurred March 26 at the St. Mary Baptist Church in Port Barre, and the second happened April 2 when the Greater Union Baptist Church in Opelousas caught fire.

Then Thursday morning the Mount Pleasant Baptist Church in Opelousas caught fire.

The churches were vacant at the time of the fires, and no one was injured.