"After they got him down on the ground, they stomped his head with (steel-toed) boots," Harris County Sheriff's Lt. John Denholm said. "They actually kicked the pipe further into him with the boots."

Trent described the pipe as being sharpened at one end. At one point, the teens tried to carve something on the boy's chest with a knife, he told CNN Friday.

"I don't know that the very beginning of the attack was racial," Trent said, "but there's no question that they were venting quite a bit of hatred in their hearts."