Mirian told her rescuers that she initially refused the sexual advances of the human smuggler who was holding her captive at the drop house in west Phoenix.

But the 27-year-old Honduran was more vulnerable than the others. She was traveling with her 3-year-old daughter, Anna (not her real name).

The smuggler, who Mirian knew as "Arturo," picked up his rifle and leveled it at her. She says he threatened to kill her and sell her child if she did not have sex with him.

She gave in.

"He hit me, ripped my clothes off and raped me very hard," Mirian later wrote in a sworn statement. "He raped me three other times during the week. Once he raped me in front of (Anna). She screamed, cried and hit him. He laughed at her and pushed her away."

The rapes continued during the four days she was held, she says. Phoenix police and federal immigration agents raided the house in October 2005, freeing Mirian, her daughter and about a dozen other illegal immigrants being held hostage there, according to police reports and court records.

Click here for a video detailing where human smuggling begins.

Mirian, who the Tribune is not fully identifying because police and prosecutors believe she is a rape victim, cooperated with investigators at first. But she disappeared a few months after the raid. Because she was not available to testify at trial, no one was ever charged with the series of sexual assaults she says occurred at the drop house on North 28th Drive in Phoenix.

Federal court records identify the man Mirian knew as Arturo as Bernardo Mancinas-Flores, who was convicted of multiple human smuggling charges for the crimes he committed at the drop house. Prosecutors used Mirian's sworn statement to seek a tougher sentence against Mancinas. Judge Roslyn Silver sentenced him to life in prison earlier this year.

In a telephone interview with the Tribune, Mancinas, who speaks only Spanish, said he does not know Mirian.

"I never had anything to do with her," Mancinas said. "The police invented that."

His lawyer argued in court motions that since Mirian did not stay to testify, her allegations of rape should not be taken seriously.

"Someone who has been 'raped' as often as (Mirian) claimed to have been would certainly seek justice when given the opportunity," lawyer Anne Williams wrote in pre-sentencing motions. "Instead, (Mirian) failed to pursue this case and testify to her allegations."

Mirian's ordeal illustrates one of the toughest obstacles to putting violent human smugglers behind bars, according to prosecutors.

Finding and keeping witnesses willing to testify against their captors is particularly difficult when the victims are illegal immigrants, said Laura Reckart, a deputy Maricopa County attorney who has prosecuted people on human smuggling charges.

Witnesses in any case involving extreme violence are often reluctant to testify because they fear retaliation, Reckart said. In the case of illegal immigrants, there is the added complication that they know they will be deported to their home countries when their testimony is no longer needed, she said.

"Trying to keep them around is difficult," Reckart said. "They disappear."

When a drop house is raided, most of the immigrants being held captive are typically turned over to federal immigration authorities for deportation, said Vincent Picard, spokesman for the U.S. Immigration and Customs Enforcement service, or ICE.

A few witnesses are held back to testify against the smugglers. Once the case is closed, they are also deported.

The most convincing argument that police and prosecutors make to would-be witnesses is that they are the only ones who can prevent someone else from meeting the same fate, Reckart said.

"The incentive is these are bad people and they need to be stopped," Reckart said. "The incentive is 'I don't want this happening to somebody else and it's going to continue on unless we stop them.'"

HUB OF VIOLENCE

The level of violence inflicted on Mirian and the other illegal immigrants at the drop house was extreme. But it was not unusual. Court records and interviews with police and prosecutors provide a grim picture of what can happen to illegal immigrants once they get to this stage of their journey.

Drop houses are the hub of violence in the human smuggling business. They are supposed to be the place where illegal immigrants who just crossed the border are kept until their smuggling fees are paid and they can be moved on to their final destinations.

The money is due as soon as the immigrants arrive at the drop house. The first thing the drop house guards will do when a new load of immigrants arrives is strip them of their shoes to ensure they do not run away. The immigrants are herded into bedrooms that have been sealed with sheets of plywood screwed over the windows, and doors that lock from the hallway.

The smugglers will demand the phone number of the immigrant's sponsor, usually a family member responsible for sending payment through electronic wire transfers.

If all goes well, the sponsor pays quickly and the immigrant is released.

But problems escalate quickly, said Phoenix police Sgt. Alex Ortiz, part of the multiagency task force that investigates violent immigrant smuggling gangs.

An unruly immigrant might be beaten or killed to keep the rest of the load docile. Immigrants who cannot come up with the smuggling fee are routinely beaten until the smuggler's demands are met.

One tactic favored by smugglers is to single out a migrant whose sponsor cannot or will not pay. The immigrant's sponsor is called on the phone. The smuggler sets the receiver down and, with the sponsor listening, beats the immigrant, often with a baseball bat or a gun.

The sponsor is told the beatings will continue until the money is paid.

A variant of the technique used on female captives is to sexually assault them with the sponsor listening.

The torture continues until the sponsor agrees to pay. If the sponsor still cannot come up with the money, the lucky immigrants are put to work cooking or cleaning in the drop house. The unlucky ones are killed and dumped in the desert, Ortiz said.

"They won't go straight to killing them," said Lt. Tim Palmer of the Maricopa County sheriff's homicide unit. "That doesn't make sense. If there's a chance that there's somebody they can contact, they'll try to beat them into complying with what they are asking. From there it will escalate until they either lose patience or they realize they are not going to get any money out of this person."

Arizona is the prime transit route for human smugglers. Drop houses are heavily concentrated in the West Valley, where there is an abundance of cheap rental housing and easy access to highways leading to California and Las Vegas, two prime destinations for smuggled immigrants, according to police and court records.

Last year, a special task force was formed among federal, state and local agencies to target the rising violence associated with human smuggling gangs, particularly at the drop house level. That unit, the Illegal Immigration Prevention and Apprehension Co-op Team, or IIMPACT, brought together investigators from the Phoenix Police Department, the Arizona Department of Public Safety and ICE.

IIMPACT only responds to drop houses in which violence has been reported.

Since it began active operations in December, the unit has responded to more than 35 drop houses in which crimes ranging from kidnapping and extortion to rape and murder have occurred.

VULNERABLE VICTIMS

For the illegal immigrants being kept at the drop house on 28th Drive with Mirian, the threats began immediately after they arrived, according to statements they later gave police. Several of the migrants said they were threatened with guns and beaten when their families were slow to come up with the money they owed.

For Mirian, the ordeal began when the drop house guards could not reach her sponsor, a friend in New York who had agreed to pay her smuggling fees once she and Anna arrived in the Valley. The first rape occurred within hours of her arrival at the drop house, she said shortly after being rescued. The last happened shortly before police and federal immigration agents raided the house, according to her statement.

Women, especially those traveling alone, are particularly vulnerable at a drop house, said Lisa Settel, the assistant U.S. attorney who prosecuted Mancinas. The women are confined for days by armed men who frequently are high on drugs and go for long periods without sleep. Unlike the open desert, the women can easily be isolated and assaulted by men who make it clear they have no qualms about hurting or killing them.

When rapes do occur, the attacker usually separates the victim from the rest of the migrants and warns the woman not to tell the others, Settel said. That would indicate the rapist is not using the assaults as a tool of intimidation, she said.

"A lot of times people are not seeing these rapes, so I have to assume they're not for the purpose of making other people pay their money," Settel said. "While they may have some effect on the people wanting to get out of that house and being scared, I don't think their sole purpose is to get the fees. I think it's for personal gratification."

LEGAL ENTANGLEMENT

Most of the immigrants rescued from the drop house on 28th Drive were turned over to immigration authorities and deported. A few were allowed to stay on temporary visas so they could be witnesses against the drop house guards.

Mirian was among those who remained. She cooperated with police and prosecutors, writing a detailed account of her ordeal as part of her application for a special visa available for victims of human trafficking.

But Mirian became ensnared in a federal law that treats victims of human traffickers differently from those of violent human smugglers, said Melissa Rodis, a private lawyer who represented her.

Trafficking requires forced labor. Victims can get a special visa that allows them to remain in the United States and apply for permanent status.

Victims of smugglers who were not forced into servitude do not qualify.

Mirian disappeared after federal prosecutors refused to endorse her application for a trafficking visa, Rodis said.

"She knew she wasn't going to have any benefits from testifying in the federal trial and she was afraid," Rodis said. "That's always a problem. If someone is going to put themselves out there, to risk their lives and their well-being to be witnesses, there has to be some kind of protection and there has to be some benefit to them."

Settel said she could not comment specifically on Mirian's visa application, but did say that without evidence of forced labor, illegal immigrants who are abused by human smugglers generally would not qualify for the special trafficking visa.

Though he did not face sex crime charges, Mancinas was sentenced to life in prison after being convicted of charges that included hostage taking and using a firearm during a crime of violence.

Mancinas denies he was a human smuggler, insisting he was just a migrant who could not pay his fees who was caught up in the police raid at the drop house.

This is part two of a three-part series.