Relatives of Palestinian teenager Mohammed Abu Khdeir, who was killed in 2014, hold posters bearing his portrait outside the Jerusalem district court on Thursday. (Ahmad Gharabli/AFP/Getty Images)

A Jerusalem court handed out lengthy prison sentences Thursday to two Israeli youths found guilty of kidnapping and brutally murdering a Palestinian teenager in a revenge attack during the summer of 2014.

The Israeli teens, both minors, were not identified. One was sentenced to life in prison and the other to a 21-year term for their roles in abducting Mohammed Abu Khdeir, 16, from outside his family home in East Jerusalem and burning him alive in a nearby forest.

A few days before the murder, which took place in the run-up to the 2014 Gaza war, the bodies of three Israeli Yeshiva students were found in a field near Hebron in the West Bank. They had been kidnapped and murdered by two Palestinians affiliated with Hamas.

The two teens sentenced Thursday, now ages 17 and 16, and their ringleader, Yosef Haim Ben-David, 31, admitted during the police investigation that Abu Khdeir’s murder was a revenge attack.

Ben-David, who is claiming an insanity plea, is likely to be sentenced next week.

All three were found guilty in November of murdering Abu Khdeir. The 17-year-old was given a 25-year maximum life sentence with another three years added for his role. The younger teen received 21 years, with the court ruling that he was not directly involved in the murder, even though he took part in the events leading up to it.

Each of the teens will also be required to pay the Abu Khdeir family $7,700 in compensation.

“This is a mild sentence. All three of them participated in burning Mohammed; all three put flammable fluid in his mouth that led to his death. And yet one of them only gets 21 years? He should have also been given a life sentence,” Hussein Abu Khdeir, Mohammed’s father, said after the sentencing was passed down.

“All we want to do is try to prevent another Mohammed from being burnt to death,” he said. “This sentence should have sent a clear message, but it is too mild and it will not stop other radicals from carrying out another attack like this.”

Hussein Abu Khdeir said that he would fight the sentencing and request that the homes of his son’s murderers be destroyed, as happens to Palestinians who carry out attacks against Israelis.

Sufian Taha contributed to this report.