Muhammad Abu Khdeir, the 16-year-old Palestinian whose body was found in a Jerusalem forest last Wednesday, was burned alive, according to Palestinian Attorney General Muhammad Abd al-Ghani Uweili.

Palestinian independent news agency Ma’an quoted Uweili as saying that a preliminary autopsy report showed soot in the victim’s lungs and respiratory tract, indicating he was alive and breathing while he was being burnt.

Israeli police say the circumstances behind Abu Khdeir’s killing remain unclear, but Palestinians believe he was kidnapped and killed by right-wing Israelis in revenge for the murder of three Israeli youths in the West Bank last month.

The Israeli youths were buried the day before Abu Khdeir disappeared.

The autopsy also showed that Abu Khdeir had a blunt force injury on the right side of his head, but he died from complications as a result of being burnt, Uweili said. The body had 90 percent burns of varying degrees,

A final autopsy will be released later, he added.

The autopsy was conducted at Israel’s Abu Kabir forensic institute in the presence of Palestinian coroner Dr. Sabir al-Aloul, the director of the Institute of Forensic Medicine at al-Quds University. Tissue and fluid samples were taken from the body for testing.