When authorities raided a traditional shrine and found blood-drenched magic charms along with a register listing young girls sold into prostitution, they were closing in on Nigeria's first conviction for human trafficking.

The crackdown has exposed a sinister subtext to the African exodus to Europe, which is claiming hundreds of lives in dangerous sea or desert crossings. Women are lured with promises of good jobs in Europe, and end up enslaved by pimps, authorities say.

First they are brought to traditional priests who starve them and perform rituals to bind them to their future employer, said Orakwe Arinze, a spokesman for the National Agency for the Prohibition of Traffic in Persons.

The women fear testifying against their captors, believing they will die or go mad for violating the oaths they have taken in the shrines.

But after a 2004 raid on a shrine in Benin City, 180 miles east of Lagos, Arinze's agency publicly burned the charms used on six victims. The six subsequently testified against the woman who took them abroad, producing a landmark conviction.

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Nine more convictions followed and 19 cases are pending, but Nigerian authorities estimate thousands of people are trafficked every year and only a small number of cases are reported.

Gooday Akhimiona, who ministers at a raided shrine, faced life in prison if convicted of trafficking but was granted immunity in exchange for informing on his clients.

He claims he knew nothing about prostitution, saying he was duped by the woman who brought six teenagers to him for rituals. "She asked that the girls should work hard and I washed their heads with leaves. When they carried me to the police station, I was shocked."

The chicken blood sprayed across Akhimiona's shrine has blackened and congealed over decades. In one corner, birds and calabashes of beer are offered to fetishes made of seashells and decorated with fur and wire. A small animal jawbone lies on a pile of chalk.

Police records show hundreds of names entered into the register of Akhimiona's shrine, along with photos of naked, unidentified European clients which are used in the rituals.

A 25-year-old named Gift fought back tears as she recounted her rescue from prostitution in Italy last year. She requested her full name not be used to protect her from retribution.

"We went to Italy through Ghana. The man said there was work there," she whispered, fingering a gold dolphin on a chain around her neck. "When I got there, they asked me to go on the street and make prostitution every day. I was shocked."

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She said a juju man, or traditional doctor, performed a ritual using chicken blood and body hair which "would make me go crazy" if she didn't work the streets in Italy.

Beside her, Esther nodded in recognition. The shy, slim 24-year-old was locked in a shrine for two weeks, starved for three days and had to offer her hair to be mixed with the blood of doves and lizards.

"I wanted to go to school abroad," she said softly. But her father has three wives and she has many siblings, "so there was no money for me to go to school here."

She was rescued by sheer chance, she said. Traffickers had brought her across the Sahara to Morocco. There a cousin happened to spot her and alerted her family in Nigeria, who recruited men in Morocco to snatch her from the traffickers and get her home.

Not all the women need to be tricked into making the journey. In a country where the average wage is less than $2 a day, many head to Europe fully aware they will work as prostitutes, authorities say.

"Some people are actually sending their daughters abroad to do this work," said Arinze, the anti-trafficking agency spokesman. "The stigma is to come home with nothing."

Many young Nigerian women are known to end up in Italy. That country has trading links with Benin City stretching back decades to when several Italians building roads in the region married Nigerian women.

"These girls are offered work, and then passed up a chain of so-called trolley boys or traffickers," said Henrietta Agun, who heads a coalition of anti-trafficking groups in Benin City, which police say is the heart of Nigeria's women-trafficking industry.

The regional government offers facilities such as the Skills Acquisition Center, where women get free courses in tailoring, cooking, computing and cosmetics. But Agun says European countries need to play their part. "If they didn't ask for our girls, they wouldn't sacrifice their lives," she said.

Agun says a typical trafficking victim pays around $150 for fake travel papers and passes through a series of intermediaries before being sold for between $6,000 and $12,000 to a pimp in Europe. People returning from trans-Sahara journeys speak of girls dying in the desert from dehydration, frostbite or botched abortions, still dreaming of jobs in Europe.

If they reach Italy, the women are told they must earn up to $50,000 to buy their freedom. Often, once they earn it the pimp turns them in to immigration authorities, ensuring they are deported and there is less competition for clients.

Investigating is dangerous. Last May, 30 men stormed the headquarters of the agency in Abuja, the Nigerian capital, destroying filing cabinets and boxes of documents. The same month, an investigator was murdered.