We're on a bus which is rattling and shaking like a cattle truck over the ruts. The twin spirits of the headlights bounce ahead of us leading the way through the darkness. Outside, a low wattage yellow light leaks out from the shacks.

Welcome to Anapra, a settlement of perhaps a 100,000 souls stretching out into the Mexican desert. It's been here 20 years but still has no tarmac road, as if everyone is hoping that one day it will simply disappear.

Rosalina Luna

It's close to one in the morning and Rosalina Luna is going home on the bus after a nine hour shift in a factory owned by Lear Automotive, an American company. Rosalina came to Juarez a year ago in the hope that some of the American dream might rub off on her in this border town.

The United States is less than 200 yards from her shack. By day you can clearly see the neat bungalows and clipped Texan lawns of El Paso through the chainlink fence. At night she lies in bed listening to the Amtrak train passing through on its way from Del Rio to Tucson.

Dangerous place

Over there, says my interpreter Roberto with a wry grin pointing to America, the rich live in the hills down unmarked tracks. On this side it's the poor.

Juarez is a dangerous place ...

Juarez is one of the most dangerous places on earth: Mexico's most powerful drug cartels use it as a beach head for their crack and cocaine pipelines into America.

Shifting tides of hungry migrant workers pass through here desperate for work. Every one comes to Juarez to make money - everyone that is except for the serial killers, who have other business to attend to.

It was around the beginning of 1995 that the police belatedly realised that a serial killer was haunting the unlit squatter camps like Anapra that ring Juarez. The bodies of young girls kept turning up.

'Too many corpses to ignore'

Sometimes in the eerie empty tracts of desert out of town, sometimes thrown down beside the highway like rubbish.

Most of them were young slim factory girls. Some had had been horrifically mutilated. Many had been strangled. Others were found with their hands tied behind their backs. Even in a place as riven with violence as Juarez there were simply too many corpses to ignore.

... but it offers freedom not found in villages

The police eventually arrested an Egyptian chemist called Sharif Sharif. He'd served time in the US for rape and certainly seemed suspicious. But within months of his arrest in October 1995, the killings resumed. The police claimed he was paying a gang from his prison cell to murder in order to make him look innocent. They arrested the gang, called the Rebels. But still the killings continue.

Sharif may well be to blame for some of the murders, but the real culprit is an attitude of mind which says that it is ok to kill women. There are thousands of young women in Juarez.

Staying sane

The Maquilas, as the foreign-owned factories are called, often prefer to hire them because they tend to be more dextrous and less bolshy than the men. They arrive at the bus stop from the Mexican countryside with little idea how to survive in a big city.

After all week on the factory floor, on Friday night they dress up and go out to the discos. It's their only way to stay sane. Standing in skimpy tops, laughing together they tell you that the small amount of money they earn is for themselves to spend as they want.

Even with all its dangers, Juarez offers a freedom that they never had in the villages. I walk across the street to a bar where the men are drinking and ask them about the killings.

Of course no-one should kill but the women bring it on themselves, they say. They dress provocatively. They don't ask their boyfriend's permission before going dancing. The men seem bewildered by the pace of social change. Most of them regard any girl walking after dark as a prostitute, to do with as they please.

Sagrario Gonzalez's body was found 20 miles down the Rio Grande. She'd last been seen getting on the bus to go home. In the police files, she looks beautiful: a young 17-year-old grinning at some party. On the next page is a photo of what remains of her skull. No one knows who killed her.

Black crosses

Venting frustration on municipal lamposts

On the day the police found her body, they informed the waiting journalists before the family. When they finally did contact the family they suggested she had been trying to earn money secretly as a prostitute. In fact she was returning from the factory.

Enraged by the apathy of a city which lets so many humans die, Sagrario's sister, Geeyamina is venting her frustration on the municipal lampposts by painting them with crosses. Black crosses on a pink background.

So far she and her friends have covered more than 500.

"We're going to continue until the police tell us to stop and start taking these deaths seriously," she says. Sadly the police probably never will.

Tonight Rosalina Luna feels safe because we are with her filming her journey. She is happy to have us along.