CHARLESTON, S.C. — A white man opened fire during a prayer meeting inside a historic black church in downtown Charleston on Wednesday night, killing nine people, including the pastor, in an assault that authorities described as a hate crime. The shooter remained at large Thursday morning.

Police Chief Greg Mullen said he believed the attack at the Emanuel AME Church was a hate crime, and police were looking for a white male in his early 20s. Mullen said the scene was chaotic when police arrived, and the officers thought they had the suspect tracked with a police dog, but he got away.

“We will put all effort, we will put all resources and we will put all of our energy into finding this individual who committed this crime tonight,” he said.

The FBI will aid the investigation, Mullen told a news conference that was attended by FBI Special Agent in Charge David A. Thomas.

Charleston Mayor Joseph P. Riley called the shooting “the most unspeakable and heartbreaking tragedy.”