JERUSALEM, Dec. 18 (JTA) — A Palestinian court has convicted three members of a terrorist cell for carrying out last week’s attack in which an Israeli mother and her son were killed. Two of the men — Abdel Nasser al-Kaisi and Ibrahim al-Kam — were sentenced Wednesday night by a court in the West Bank town of Jericho to life imprisonment with hard labor for opening fire on a car carrying an Israeli family from the West Bank settlement of Beit El. The third man, Ibrahim Massad, was sentenced to 15 years for driving the getaway car. All three, who were 20 years old, were members of a cell of the Damascus-based Popular Front for the Liberation of Palestine, which militantly opposes the peace process. After carrying out the attack on a West Bank bypass road, killing Ita Tzur, 42, and her son, Ephraim, 12, the terrorists fled to the nearby town of Ramallah, which is under Palestinian self-rule. The two weapons used in the Dec. 11 attack were found in the possession of Massad, who was arrested Wednesday. The two others were arrested by Palestinian security forces the night of the attack. In a crackdown on the PFLP cell in the Ramallah area, Palestinian Authority security forces arrested dozens of other Palestinians, some of whom were suspected of having aided the terrorists. Earlier Wednesday, settlers in Beit El laid the cornerstone for a new neighborhood that will be built in the settlement in memory of Ita and Ephraim Tzur. The Israeli government has not approved construction at the site. Settlers said that the cornerstone-laying was a symbolic act that took place on the seventh day after the slayings, adding that they did not intend to proceed with any building of the new neighborhood on Artis Hill until the government gave its approval. The Palestinian court’s speedy convictions of the three make it unlikely that an Israeli request for their extradition will be honored. Under the terms of the Israeli-Palestinian accords, Israel can request the extradition of suspected terrorists, but the Palestinian response can be delayed if the suspects are serving prison terms in the self-rule areas. This week’s convictions would not be the first time that Palestinian courts have acted swiftly to pre-empt an Israeli extradition request. When asked whether the three would be extradited to Israel, Jibril Rajoub, who is in charge of all Palestinian security forces in the West Bank, told reporters after the court handed down the sentences, “It will never happen.” Israel Radio reported that the terrorists who carried out the attack were acting under orders from the PFLP leadership in Damascus, which funds the group and is considered more extreme than the group’s leadership in the territories.