WALNUT CREEK, Calif. -- The promise of a good job and a nice place to live turned into a nightmare for a Peruvian woman who authorities say was lured to the East Bay by a Walnut Creek real estate agent in what ICE investigators say appears to be an increasingly common kind of human trafficking case.

Investigators say many times victims come from all over the world to work as nannies and end up virtually being held captive, threatened with jail or deportation if they complain.

Law enforcement officials say it can occur right under your nose, much as it did behind the closed doors and curtained windows at a Walnut Creek apartment complex.

It was in Apartment #64 of the Cypress Creek Apartments where federal investigators say a shocking case of human trafficking and indentured servitude took place for 19 long months in plain sight of neighbors who had no idea about what was going on.

"I saw that lady sometimes in the laundry room but when we say 'Hi,' I think sometimes that she doesn't speak English," said Cypress Creek resident Sharon Zhao.

This federal criminal complaint details an American dream turned immigrant's nightmare. Immigration and Customs Enforcement (ICE) officials level charges against Mabelle de la Rosa Dann, an East Bay real estate agent who allegedly conspired to bring in and harbor a Peruvian woman illegally to exploit her as a free domestic servant.

"It's even been a real eye-opener to me to learn of people being held in just your average suburban homes," explains ICE Special Agent Kit Welsh. "It's modern day slavery."

Agent Welsh and ICE officials won't speak specifically about Dann's case, but the complaint alleges that in July 2006, Dann brought Zoraida Pena-Canal from Peru to Walnut Creek under a three-month visitor's visa.

Investigators say Dann promised Pena she'd live in a big house with a private bathroom and would be paid up to $600 a month to care for Dann's three young boys.

Instead, ICE says Pena became a virtual prisoner for almost two years

Dann, her children and Pena shared a two-bedroom apartment. Investigators say Pena was forced to sleep on the living room floor while working from dawn to dusk every day, cooking, cleaning and caring for the children.

The complaint alleges Dann didn't pay Pena a salary and actually charged her $15,000 for clothing and other expenses.

KTVU repeatedly tried to contact Mabelle Dann to get her side of the story. On Sunday, a worker inside her new apartment a few blocks away from the Cypress Creek complex said Dann was unavailable.

On Monday, Dann saw KTVU's camera and covered her face with what appeared to be a ski mask and goggles as she took her children to school. She declined to talk to us about her case. But law enforcement officials say similar cases are prompting a reconsideration of the meaning of human trafficking.

"I think for most people, they think of human trafficking, they think of sweatshops and agriculture workers," says ICE Special Agent Walsh. "But what we're seeing more of now are individual acts of trafficking [with] people being held as domestic servants."

Dann allegedly confiscated Pena's passport and visa and physically and verbally abused the nanny, threatening her with deportation if she talked to outsiders.

"What makes it very difficult for us is people are coming from an environment in which they can't trust the police,” said U.S. Attorney for Northern California Joseph Russoniello. “There's a reluctance and a hesitation for these people to come forward."

The complaint alleges Dann smashed Pena's radio and a television set, to prevent her from listening to Spanish language programs that would, quote "put ideas in her head."

Investigators say Dann told Pena: "When you come to the United States, you must suffer."

"They may not be physically restrained, but they're told, 'You're here illegally,'" says Special Agent Walsh. "They may not speak the language, they're told 'If you cause problems or try to get away, I'll report you to immigration and they'll put you in jail.'"

Investigators say Dann even rationed Pena's food, weighing the meat she purchased and hiding fruit from Pena. Neighbors say Pena often appeared daily in the same clothes.

Despite her apparent circumstances and the language barrier, a teacher at Dann's children's school says the nanny was an excellent caretaker.

Last April, Pena confided in a teacher. It was teacher who called in immigrant aid organization La Raza, which took in Pena and contacted ICE.

Prosecutors say the nanny is still in the Bay Area pending Dann's trial. Witnesses who may have immigration problems can reside here during legal proceedings. Pena could be put on a path to citizenship afterwards.

"I can seek that they be protected; that they stay in the United States as material witnesses," said U.S. Attorney Russoniello.

Mabelle Dann heads to court Wednesday on charges that she conspired to bring in and harbor an illegal alien -- charges that could include up to five years in prison.