Defense officials expect significant progress soon in the investigation of the Fogel family murder in the West Bank, after the Israel Defense Forces made another raid in the northern West Bank yesterday.

Since the murder last month, the army has arrested dozens of residents of the Palestinian village nearest the settlement of Itamar, where the murder took place. Some of those detained were soon released, but others are still being interrogated by the Shin Bet security service.

The Fogel family - father Ehud, mother Ruth and three of their children - were stabbed to death in early March. The three children were Yoav, 11, Elad, 4, and Hadas, 3 months. Another daughter Tamar, 12, discovered the bodies after coming home from a youth-movement activity. Two other siblings were alive and unharmed.

Later, investigators found that the killers had climbed over the electric fence around the settlement and escaped the same way. The security system registered contact with the fence, but a patroller sent out to the fence did not notice anything suspicious and the alert was called off.

The attackers remained in Itamar for more than two hours before escaping to the village of Awarta, investigators believe. The village has been under curfew for several days, and house-to-house searches have been conducted, with dozens of residents detained.

In the investigation, the Shin Bet, district police and IDF have worked together to find the killers. Many of the assumptions regarding the attack, including some voiced on the Palestinian side, spoke of the killers acting alone and with good knowledge of the area, without following orders from the headquarters of any particular organization.

IDF Central Command is eager to make progress in the investigation, both because of the killing's brutal nature and out of fear extremist settlers would seek revenge for the murders by going after the lives and property of innocent Palestinians in nearby villages.

The residents of Awarta and senior officials in the Palestinian Authority have complained in recent days about the IDF's conduct in the village. Movement to and from the village has been constrained, and some residents cited serious damage to property during some of the search raids. Palestinian Foreign Minister Riyad Al-Malki said Israel was slowly demolishing the village to use its land for the expansion of Itamar.

The settlement itself, meanwhile, marked 30 days since the murder. During the event, a cornerstone was placed for a future beit midrash - a place of Torah study - to be named after the father of the family, Ehud Fogel.

One speaker at the memorial was a former chief military rabbi, Avichai Rontzky. "We will leave this great crisis stronger," he said. "I'm sure of it."

Sephardi Chief Rabbi Shlomo Amar said yesterday that "there is individual grief and general grief. Every home in Israel is mourning this. The murders have gone as low as you can go. They shouldn't think our sensitivity is a weakness. It comes from a depth they do not know." The head of the local authority, Gershon Mesika, said the ideal of the Land of Israel will not be broken.