Enforcement of California's anti-human trafficking law, the first kind in a U.S. state, has hit snag as authorities found it too difficult to prove the crime, a newspaper report said Saturday.

No human trafficking cases have been tried in California after it became the first state to enact a federally drafted law cracking down on the crime last year, according to the Los Angeles Time.

Despite some well-publicized cases, authorities said existing law did not provide the legal tools to fight the crime, instead forcing them to use other charges, which often carry little or no jail time.

Governor Arnold Schwarzenegger signed the bill into law in December 2005 amid much fanfare and with the hope that it would become a national model, saying it would help put an end to "a horrific crime that our society cannot abide."

When the state law passed -- providing penalties of three to five years in prison and four to eight years if the victim is a minor -- detectives dramatically stepped up their investigations, helped by federal grants aimed at fighting the trafficking rings.

But police found it was difficult to prove whether the victims were being kept against their will or were enduring their hardships willingly as a step up the economic pecking order.

Authorities said victims were often reluctant to tell the truth because they were afraid of law enforcement officers and possible retaliation from their captors.

Lawmakers has believed the law was particularly important in California's immigrant communities, the sites of several well- publicized cases over the last decade.

The U.S. Justice Department estimates that 17,500 people are enslaved in the nation's fields, factories and brothels, with a disproportionately large share in California, although the department acknowledges the figure may not be completely reliable.

A Justice Department report said the criminal rings that bring these workers to the United States have a more lucrative business than drug traffickers because of the low cost of slave labor and the small risk of getting caught.

Supporters earlier believed that taking into effect the new law could help persuade victims to cooperate, as it allows them to receive housing and medical assistance, obtain legal residency and receive job training if there is a conviction.

Meanwhile, federal authorities are struggling with the human trafficking law as well, with few convictions have been made since the federal law was passed in 2000, the Los Angeles Times report said.

The Justice Department has expressed disappointment with its own progress, reporting in September that only 122 laborers and prostitutes qualified for victim benefits, 14 fewer than in the previous year.

Source: Xinhua