The silent, grainy footage, taken from a security camera, shows Nathaniel Brazill with his arms extended and his back to the camera. He points the gun for several seconds before pulling the trigger. The victim, English teacher Barry Grunow, is not visible when the gun is fired.
Afterward, the boy recoils and he heads down the hall, pointing the gun at a math teacher and student before fleeing.
Chief Judge Walter Colbath Jr. ruled July 7 that the minute-long videotape is a public record like other evidence released in the trial, but he banned any reproductions.
The screenings were held at the Palm Beach County Courthouse's 300-seat jury assembly room. About 20 members of the media and 40 other viewers attended the first public showing.
Those attending must sign a form pledging not to reproduce the videotape, and bailiffs were to monitor the screenings.
Brazill, an honor student at Lake Worth Community Middle School, had been sent home on May 26 the last day of the school year for throwing water balloons. He returned with a .25-caliber pistol he had stolen from his grandfather's bedside table. Brazill told police he shot Grunow after the teacher refused to let him say goodbye to two girls in the teacher's class.
Brazill told police that he didn't mean to kill anybody and the gun went off accidentally. He cried when he learned Grunow was dead.
The teen is charged with first-degree murder and faces life in prison if convicted. No trial date has been set.
Brazill's defense attorney, Robert Udell, showed the video to The Palm Beach Post on Thursday. He said the tape won't seriously affect the case, because the real issue is what the teen was thinking, to determine whether the shooting was murder or an accident.