Seven former juvenile boot camp guards and a nurse were responsible for a teenager's death because they repeatedly hit him and failed to get him help, a prosecutor said Wednesday as their manslaughter trial began.

Prosecutor Pam Bondi described a video of the guards striking Martin Lee Anderson with their fists and knees at the military-style boot camp in January 2006, as the 14-year-old lay limp for most of the time and the nurse watched.

She also said the guards held their hands over the boy's mouth and shoved ammonia capsules up his nose.

"Their job was to teach discipline, but first and foremost to do no harm," Bondi said of the defendants, later adding: "This was no accident. This was a child who was killed."

Defense attorneys said in their opening statements that Anderson died of a rare genetic blood disorder and not the actions of camp employees.

"This case didn't start on Jan. 5, 2006, it started Jan. 15, 1991, when Martin Lee Anderson was born with sickle cell trait," said Robert Sombathy, attorney for guard Patrick Garrett.

An initial autopsy by the local medical examiner said the death was due to natural complications of the disorder. But a special prosecutor ordered a second autopsy by another doctor, who found the guards suffocated Anderson with their hands and by making him breathe ammonia.

Anderson's parents watched intently as Bondi described the videotape and the investigation of his death. His father held his face up with his hands at times before the defense spoke.

The case has generated intense media attention and civil rights groups doubt a mostly white jury will be impartial. Anderson was black; the guards are white, black and Asian.

The seven guards and the nurse face up to 30 years in prison each if convicted of aggravated manslaughter of a child.

About 30 protesters gathered outside the court, which is across the street form the now-closed camp. The NAACP's Florida chapter demonstrated against the trial because five of the six jurors are white — the other is Asian — and the trial was not moved from Bay County in the Florida Panhandle. Some of the seated jurors had seen the videotape.

Benjamin Crump, the attorney who represented Anderson's family in a lawsuit against the state, told protesters that the defense was focusing on sickle cell trait because attorneys were "looking for any excuse to justify what happened on the tape."

Anderson died in January 2006 after being taken to a hospital from the boot camp, which was run by the county sheriff's office.

He had been sent to the camp for a probation violation and became lethargic during a physical fitness test shortly after arriving. The videotape showed him after he collapses and was caught on an exercise yard surveillance camera.

The Florida Legislature dismantled the state's system of youth boot camps after Anderson's death. The case also led to the resignation of the chief of the Florida Department of Law Enforcement and public protests at the state Capitol.

The Legislature agreed to pay Anderson's family $5 million earlier this year to settle civil claims.