Earlier this month, a Palestinian man began a 98-year jail term for murdering young father Asher Palmer and his baby son by throwing a rock.

The ruling against Waal al-Arja is unusual in the Israeli military courts that deal with Palestinian crime, and a coup for the British-born lawyer who represents the victims’ family.

While Palestinian stone-throwers are often prosecuted, they are rarely sentenced to murder because there is a lack of legal precedent for defining rocks as a murder weapon and, historically, judges have tended not to rule premeditation in rock attacks.

The attacker threw a rock from an oncoming vehicle at Asher Palmer’s car in the West Bank, injuring him and causing him to lose control of the car, which subsequently overturned.

“Only I believed there would be a sentence for murder,” said Adrian Agassi, lawyer for Michael Palmer, whose son and grandson were killed a year and a half ago.

Mr Agassi, a Carmel College graduate who made aliyah in 1986 and went on to stints as an army lawyer and a military judge, pushed the military prosecution to demand a murder sentence, instead of taking the normal approach that stone throwing is wrong but the aim is not to kill.

He believes that the sentence will have a deterrent effect on other stone throwers who realise that the stakes have been raised, sending out a message that “enough is enough”.

He also hopes that, with a stone defined in the Palmer case as a murder weapon, civilians will be provided with the same justification for opening fire on stone throwers as those who shoot back at those wielding guns — a suggestion that will meet with controversy in the Israeli legal establishment.

The sentencing of al-Arja at Ofer Military Court was unusually emotional, as the father of the victim took the unusual step of addressing the bench. He spoke of how he saw “Asher’s body wrapped in a tallit, and a little box on top, in the box was Yonatan’s body.”

Mr Palmer, who made aliyah from America, talked about how his grandson’s life was cut short just as he was starting to speak. In an interview after the hearing, he said: “When you have a murder trial, the victim can’t be there and I’ve seen that there’s a tendency for the murderer, with their family crying in the court, can be seen as a kind of victim.” He “wanted it to be clear what was now missing from the world,” and to humanise the victims before a sentence was passed.

Asher Palmer, a settler who lived in Kiryat Arba, had studied in yeshivah, married, and was starting to study engineering in Jerusalem, his father said.