The Palestinian attorney general says the autopsy on the Arab teenager killed in a suspected revenge attack show he was burned to death.
The charred body of Mohammed Abu Khudair was found in a Jerusalem forest Wednesday about an hour after he was forced into a car by kidnappers.
A Palestinian forensics official on Saturday reported finding smoke in his respiratory canal, meaning that Khudair was breathing while he was being burned.
His father said the teen's body was burned beyond recognition and could be identified only by his DNA. The Palestinian attorney general said Khudair suffered burns over "90 percent of his body."
Israeli police have not yet determined who killed the boy or why. They said they are investigating whether the killing was in response to the kidnapping and murder of three Israeli teens found buried earlier in the week.
Israeli officials have blamed Hamas for the three teens' murders, but Hamas denied involvement.
However, some Hamas leaders have said such an action would be a justified response to what they view as Israeli injustices.
Meanwhile, the parents of Mohammed Abu Khudair's cousin say Israeli police badly beat their son before arresting him Thursday.
Tariq Abu Khudair is a U.S. citizen visiting Jerusalem. His parents said they barley recognized their son's badly swollen face when they saw him in a hospital.
A video shows police beating a suspect who the parents identify as Tariq.
Israeli police say he was part of a group of masked youths carrying knives and that the video was altered and is inaccurate.
State Department spokeswoman Jen Psaki says the U.S. is profoundly troubled by the alleged police beating and strongly condemns any excessive use of force.
Clashes between Israeli police and Palestinian protesters continued Saturday in East Jerusalem and other towns. Demonstrators threw rocks at Israeli police who responded with tear gas and stun grenades.
Israeli police increased security in anticipation of more demonstrations following Khudair's funeral. Friends and family buried the teen Friday in a cemetery in the Arab neighborhood of Shuafat.
Palestinian militants fired rockets and mortars from the Gaza Strip border, while Israel carried out several airstrikes in Gaza.
There were no immediate reports of causalities.
Some information for this report comes from AP and Reuters.