A 14-year-old boy beaten by guards at a Florida boot camp died because guards suffocated him, a coroner has said.
Martin Anderson was beaten on his first day at the camp
The findings contradict a first autopsy which said Martin Lee Anderson died from a normally benign blood condition.
The teenager's body was exhumed after a videotape showed guards at the Bay County camp kicking and punching him.
Dr Vernard Adams, who carried out the second autopsy, said Martin Anderson died because his mouth was blocked and was forced to inhale ammonia fumes.
The "forced inhalation" caused his vocal cords to spasm and block his upper airways, the Hillsborough County medical examiner concluded.
"Martin Anderson's death was caused by suffocation due to actions of the guards at the boot camp," Mr Adams said.
He said that while the guards' beating left bruises, it did not contribute to his death.
'Justice is served'
The first autopsy, by Bay County Medical Examiner Dr Charles Siebert, said Martin had died from complications of sickle cell trait.
His findings were disputed by the boy's family, and led Florida Governor Jeb Bush to order an investigation that led to a second autopsy.
Mr Bush said he was disturbed by the findings of the second autopsy and pledged to provide the resources to ensure "justice is served".
The lack of any arrests over the beating of Martin Anderson on 5 January, and his death a few hours later in hospital, sparked protests in the state Capitol.
It forced lawmakers to scrap the military style camps and led to the resignation of the state's top law enforcement officer, the Associated Press reports.
The beating happened on Martin Anderson's first day at the Bay County Sheriff's boot camp for juvenile offenders.
The camp surveillance videotape showed the guards roughing him up and shoving ammonia pills up his nose.
The teenager had been sent to the camp for violating probation by trespassing at a school after he and his cousins were charged with stealing their grandmother's car from a church parking lot.