On a still, hot, August afternoon you can only hear the bleating of the lambs and the occasional bark of a dog. There are few places more exposed and isolated in the West Bank than the cluster of tents and caves that is home to Khalil Nawaja, his wife Tamam, their two sons and their 50 sheep.

It was close to here that the couple were severely beaten last summer by four masked, club-swinging Jewish settlers in the barley field. Tamam, her face still bleeding after being clubbed in the jaw, was driven in an Israeli Army ambulance to Beersheeva's Soroka hospital, where she required three days of treatment.

And it was here that they received the news last week that the Israeli police had closed an investigation without making charges, even though the attack was caught on video, causing shock and outrage across Israel and beyond when it was shown on television last year.

George Mitchell – President Barack Obama's point man for kick-starting Middle East peace talks – yesterday pressed Israel to halt construction of West Bank settlements as a "confidence-building" gesture toward the Palestinians. As the Israeli Prime Minister Benjamin Netanyahu headed into the meeting with Mr Mitchell which took place in London, he stressed that settlers were entitled to "continue living normal lives".

But it is the Palestinian Nawajas who have found it difficult to live "normal lives" since the attack on their five-acre plot in the arid and remote hill country south of Hebron in sight of the red-roofed Jewish settlement of Susiya. "I cannot leave this place for a single day or the land will be theirs," said Mr Nawaja, 61, who was also injured in the attack 14 months ago.

The West Bank Area C – unlike the Palestinian cities – is under direct Israeli military control. But Mr Nawaja clearly feels unprotected from all sides. "We are in the front line. We are protecting the land. But the [Palestinian] Authority does not seem to care about the land or the people. If leave tomorrow I will lose the land."

The closure of the lengthy Israeli police investigation into the attack on the Nawajas has cast fresh doubt on the efficacy of law enforcement against a violent minority of the 300,000 Jewish settlers in the West Bank. According to one human rights agency, Yesh Din, around 90 per cent of investigations it monitored in 2005-6 into complaints by Palestinians against settlers – and 79 per cent of ones about assaults – ended without an indictment.

Lawyers representing another agency Btselem are appealing for an order to re-open the Nawaja case. The police file shows detectives ran up against a wall of silence from most Jewish residents. In one revealing extract from the documentation, an Israeli shepherd repeatedly invokes his "right to remain silent" and when asked if he can name anyone who was involved declares: "Does it say rat on my forehead?"

The fact that the faces of all four of the assailants were covered with shirts underlines the limitations of Btselem's enterprising policy of issuing video cameras to vulnerable Palestinian residents. But there are doubts about how quickly the police – despite describing the incident as "grave" – started to hunt in earnest for suspects and evidence.

It was nine days before they searched a settler farm, where the Nawajas were convinced their attackers had come from, and indeed returned to after the incident was over. The search yielded evidence including shirts similar to those in the video clip, two picks with club-like handles, and five 9mm bullets.

Although the owner of the farm, Dalia Har Sinai – a well-known local settler whose husband was killed by two Palestinian gunmen early in the intifada – accompanied police on their search, there are no indications that they formally questioned her. When The Independent contacted her house by telephone yesterday, Mrs Har Sinai was said to be on holiday but one of the building's apparently temporary occupants added: "She has nothing to say."

Judaea and Samaria [West Bank] police would say only that "no evidence linking the owner of the farm to the event has been found. There was indeed footage documenting the violence but all the assailants were masked. Nevertheless, police managed to locate seven suspects who were detained and one was brought to court for an extension of his remand." The statement added that the tractor had been found, which preceded the four assailants to the scene of the attack. Its owner had been "interrogated".

"Everyone seems to know who these men are except the police," Mr Nawaja said this week.

It was not the first time his family had been attacked on the land, the deeds of which date back to Ottoman times and show as his family's, according to Mr Nawaja. A year earlier, two unmasked settlers arrived with around 200 sheep who proceeded to eat the young crops. "I said: 'Why are you doing this? The land belongs to me.' They said: 'All the land is ours.' Then I tried to shoo the sheep away," Mr Nawaja recalled.

At this point, he says, one of the settlers grabbed him by the shirt collar while another smashed a stone against his face, dislodging two of his teeth: "When they saw the blood they took their sheep and ran away." Mr Nawaja was then helped by Israeli soldiers who called an ambulance and advised him to lodge a complaint with the police. Shown a series of photographs on four separate occasions of possible suspects, Mr Nawajah was scrupulous in telling police than none of them were the right men. "I recognised some of them but none were the men that attacked me."

About the second incident, he was initially much more hopeful, thanks to the presence of mind of his daughter-in-law Muna, who brought her Btselem video camera with her when the family was summoned to help Mr Nawaja's nephew Imran after he was threatened on the family's land. She hid behind the crops filming part of the attack. Imran testified that he was knocked to the ground and hit all over his body and, though dizzy, saw his uncle similarly attacked and managed to recover enough to throw some stones in retaliation.

Even if the demand being pressed by the Americans now is agreed by Israel, a freeze on new settlement construction will do little to help the Nawajas' sense of security; for that they may need the removal of Susiya settlers in the two-state solution that is presumed to be President Obama's endgame.

"They [the settlers] want us to leave and go to [the nearby town of] Yatta," Tamam Nawaja said: "They want us to leave this land, but it is our land."

US talks yield hope

The prospect of an early resumption of US-sponsored direct peace negotiations between Israel and the Palestinians appears to be inching closer following four hours of detailed talks at a London hotel between the American envoy George Mitchell and the Israeli Premier Benjamin Netanyahu.

The Israeli delegation claimed afterwards that it was nearing a "bridging" agreement with Washington on settlement building, the Palestinian pre-condition for restarting the moribund peace process.

But even if the mood music suggests a compromise by Mr Netanyahu and that Israel is willing to restrict settlement construction, it is not a complete freeze on settlements in occupied territory that the Palestinians, with backing from the US, had demanded. In particular, there is no indication that Israel is preparing to accept any curbs on its highly controversial building activities in Arab East Jerusalem. Israel's refusal to budge on this has strained relations with Washington.

Expectations are nevertheless high that President Obama wants to make an announcement on the resumption of peace talks before the end of next month. That will require substantial progress being notched up when Israeli officials sit down again with Mr Mitchell in Washington next week.