Three teenagers pleaded not guilty Wednesday in a series of brutal beatings that killed one homeless man and seriously injured two others the same night.

One of the Jan. 12 attacks was captured on a university surveillance tape that shows two young men with baseball bats repeatedly hitting a homeless man on a sidewalk outside a building.

Authorities have said the tape, which sparked public outrage, helped lead to the arrests of the three 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.

Gaynor was beaten with a baseball bat while he slept on a park bench and was shot with a paintball gun.

Perez was assaulted with a golf club outside a nearby church, and Pierre was bludgeoned with a bat on the Fort Lauderdale campus of Florida Atlantic University, the attack caught on tape.

Hooks and Ammons could face the death penalty if convicted; Daugherty is being tried as an adult but faces a maximum sentence of life in prison because of his age.

Under Florida law, people who take part in a crime can be charged with murder if someone is slain, even if they didn't commit the actual killing.

Police also are investigating whether the teens may have been involved in five other assaults on homeless people who came forward after the Jan. 12 attacks.