"I went to that church in Charleston and I did it," he said, then laughed.
"Did you shoot them?" a law enforcement officer asked a calm and composed Roof.
"Yes," Roof replied, followed by another laugh.
Asked how many people he killed that day, the young man in the mushroom-shaped haircut replied calmly: "If I was going to guess, five maybe. I'm really not sure."
In the video, the self-described white supremacist said he opened fire with a Glock .45-caliber pistol.
