Fort Lauderdale, Fla. ? Three teenagers accused in a series of brutal beatings that killed a homeless man and seriously injured two others the same night pleaded not guilty Wednesday to charges of murder and attempted murder.

In one of the attacks, captured on a university surveillance tape, two young men with baseball bats repeatedly hit the victim as he lay on a sidewalk and tried to block the blows with his hands. In the other attacks, authorities said the assailants used a paintball gun, bats and a golf club.

The videotaped attack sparked public outrage and helped lead authorities to the teens.

Brian Hooks and William Ammons, both 18, and 17-year-old Thomas Daugherty were indicted earlier this month on murder charges in the killing of 45-year-old Norris Gaynor and attempted murder in the beatings of Raymond Perez and Jacques Pierre.