By Martin Asser BBC News Online

There's another significant anniversary this week, but not one that's attracted the sort of attention the 11 September commemorations have.

On 16 September 1982, under the watchful eye of their Israeli allies who had encircled the area, Lebanese Christian militiamen entered Beirut's Sabra and Shatila refugee camps bent on revenge for the assassination of their leader Bashir Gemayel.

Refugee camps like Shatila still lack the most basic services

There followed a three-day orgy of rape and slaughter that left hundreds, possibly thousands, of innocent civilians dead in what is considered the bloodiest single incident of the Arab-Israeli conflict.

If Americans approached the 11 September anniversary with trepidation, many residents of Shatila camp, and its more run-down neighbour Sabra, have been dreading the milestone on Monday which marks two decades of pain and the futile search for justice.

Take Um Ahmad, who still lives in the same house where she lost her husband, four sons and a daughter when a thick-set militiaman carrying an assault rifle bundled everyone into one room of their hovel and opened fire.

Only she and her daughter Suad survived the carnage, their survival aided by the fact of their being hidden under the broken remains of their loved-ones. Another daughter, Nuhad, escaped by hiding in a cupboard in the kitchen.

Opening wounds

"I'd rather not talk about what happened," Um Ahmad says as she bids us sit down in the room where her family perished. "What's the point of opening old wounds?"

But talk she does, despite herself, telling us how the events unfolded and recalling each of her four sons by name, Nizar, Shadi, Farid and Nidal (whom they called Bassam because of his bright smiling appearance).

A terrible fate awaited the boys in this family photo

I learn that, for many years, the survivors did not set foot in the room where the killings took place. But this year they have decided to open it up, the only sign of its tragic history a large funereal-looking banner in Arabic over the door which says: "There is no god but God".

When I ask if she has a photograph of her boys, Um Ahmad begins rummaging deep inside a cupboard where she produces a framed colour picture of three sweet-looking kids. The youngest, barely out of nappies, had three bullets drilled into his head, she says.

Where did Um Ahmad come from in Palestine, I ask, wanting to change the subject.

"Safad, on the border with Lebanon," she says, a pale smile on her face for the only time during my visit.

"I was five years old in 1948 when we left. I can still remember it, like a dream," she adds.

Failed prosecution

Every year since 1982 has been a bad year for Um Ahmad, but 2002 has been among the worst.

Residents of the camps remain haunted by 1982

In 2001 lawyers representing her and two dozen other victims' relatives attempted to have Ariel Sharon (Israel's defence minister at the time, now prime minister) tried for the massacre under Belgian legislation, which grants its courts "universal jurisdiction" for war crimes.

There had been great enthusiasm about the case in the camps. Mr Sharon, after all, had already been found to bear "personal responsibility" in the massacres by an Israeli commission of inquiry (which concluded he shouldn't hold public office again).

But the relatives' hopes were dashed again in June 2002, when the Belgian judges ruled that the case was inadmissible.

The fact that Mr Sharon had got off on a technicality (thanks to his absence from Belgium) is of little comfort to people who have spent every day of the last 20 years living with the consequences of the massacres.

In fact, many in Shatila rounded on the lawyers for enlisting them in an exercise that, in the end, had only - to paraphrase Um Ahmad - "opened the old wounds again".

Nor was there any satisfaction in the camps that the man who had led the killers, Elie Hobeika, himself met a violent end this year. Death in a car bomb followed his announcement that he would testify against Mr Sharon in Belgium.

Anniversary plans

During my visit to Shatila few people knew how they were going to spend the anniversary.

This is the only monument to the victims of 9/16

It will certainly be a far cry from the ceremonies in New York and Washington, where American leaders told the world that its pre-eminent military power was going to ensure that justice for the victims would triumph over evil whatever the cost.

The Palestinian survivors of the 1982 massacres will probably gather for speeches at the place where their loved-ones were buried en masse - a dusty vacant lot marked by a pathetic temporary monument of breezeblocks.

But there will be no internationally-observed minute's silence for the innocent victims of Sabra and Shatila, or global news coverage about the survivors and their miserable existence at the scene of this evil crime.