The Shin Bet security service is questioning four Jewish settlers who are suspected of plotting to detonate a powerful bomb in the courtyard of a school for Arab girls in the A-Tur neighborhood of East Jerusalem two weeks ago.

Police sappers discovered the bomb, comprised of two gas balloons and two barrels of gasoline, in a cart. It was set to go off at 7:35 A.M., when the 1,500 students at the school line up in the courtyard for their morning assembly. Police are also considering the possibility that the bomb was intended to be detonated on the sidewalk between the school and the adjacent Mukassed Hospital.

The police had not received any intelligence information about plans for an attack in A-Tur. The Jewish suspects were apprehended by a patrol unit that happened to notice them in the neighborhood before dawn on Monday, April 29. The policemen noticed a commercial vehicle pulling a cart and mounted a pursuit, suspicious of the vehicle's activity at that time of the day.

The suspicious vehicle stopped near Mukassed Hospital, on the main street of the neighborhood. Shlomo Dvir (Zeliger), 29, and Yarden Morag, 25, both from the settlement of Bat Ayin, got out of the car and started to untie the cart. The police officers approached and asked the two what they were doing and they responded that they were fixing a flat tire. After the two refused to identify themselves or explain where they were headed, the police decided to take them in for questioning.

In the car, the police discovered guns that Dvir and Morag were not licensed to carry. A sapper was then called in to check the cart, finding and neutralizing the explosive device.

Dvir and Morag were arrested and questioned by the Shin Bet, without being allowed to meet with their attorney, Naftali Wartzberger. A full gag order was also imposed on the investigation.

During a search at Bat Ayin, police also arrested Ofer Gamliel, 42, on suspicion of assisting the other two residents of the settlement in preparing the bomb. A fourth suspect - Yosef Ben Baruch, from Havat Maon - was subsequently arrested in the case.

Police are now checking whether the four were involved in a series of terror attacks carried out against Arab targets during the past two years. These attacks have included seven shooting deaths of Palestinians on roads in the West Bank. Several unknown groups have taken responsibility for these attacks, in which 10 other Palestinians were also injured.

Sources involved in the investigation into the road shootings said that it appeared that the suspects under arrest were not linked to these incidents. But the Shin Bet and police are also investigating whether the four suspects were involved in the school courtyard bombing in the village of Tsur Baher in East Jerusalem that took place in early March.

Nadav Shragai adds: The Yesha council of Jewish settlements issued a statement on Friday condemning the alleged bombing attack against Arabs. A group of rabbis also demanded earlier last week that the suspects be allowed to meet with their attorneys.