Read all of the Tulsa World’s coverage of House Bill 1804.

Uncertain what might happen, many illegal immigrants are leaving the state for Mexico.

CASA BLANCA, Mexico -- If Oklahoma's House Bill 1804 is supposed to force people to leave the state and return to Mexico, it's working.

The law goes into effect Thursday, but it is already causing a reverse migration of illegal immigrants -- and their U.S. citizen children -- to Casa Blanca, a north-central Mexican town that has long supplied hundreds of illegal immigrants to Tulsa.

''You don't hear people talking about anything else here,'' said Lilia Esparza, who has been the town nurse since 1986. ''Everywhere I hear the phrase 'they're coming back!' ''

The Tulsa World revealed the Casa Blanca pipeline in a 2006 series of stories, which showed some 3,000 Tulsa workers, mostly illegal, had ties to the area.

Now, facing fears of lost jobs, homes and children in the United States, the tide is flowing back.

Esparza's statistics show that 49 families and 88 other U.S.-born children returned

Whether that trend will continue after the law goes into effect is an open question, especially if there isn't a harsh police enforcement effort.

Those returning home face a bleak scenario: camping out in Tulsa-bought trucks or crumbling, burglarized adobe homes this winter, huddling around campfires in a lawless small town on the frigid Mexican highlands.

The Oklahoma law makes it illegal to knowingly transport illegal immigrants, and it throws up state barriers to hiring of illegal immigrants.

It also requires employers seeking state contracts to use the federal status verification system for its employees and requires identification and proof of citizenship before people can receive certain benefits.

But, to the people of Casa Blanca, the consequences are starker.

''People said, 'What if we just get deported without warning? Will the kids stay behind?' '' Esparza said. ''There were rumors of massive, forced adoptions. They thought even newborns would be taken away.

''In September, the rumor was that immigration officers would be coming into the classrooms in Tulsa, which is why so many young kids were sent back to Mexico,'' Esparza said.

Esparza said a woman came into the clinic recently in Casa Blanca. She had gotten pregnant in Tulsa, but decided to come home to Mexico to give birth because she was afraid her baby would be taken from her in the hospital.

Juan Becerra, 40, a farmer in Mexico, lived in Tulsa for seven years before returning in early October. Becerra laid water mains, built sewers, roads and sidewalks for a contractor, making $12 an hour.

''Rumors are running that they're going to start picking people up before Nov. 1, and on Nov. 2, they're going to pick up anyone they see walking around,'' Becerra said.

Fatima Soriano, a 24-year-old medical school resident serving the town, said although many parents of the children sent home to Casa Blanca are going to try to stay in Tulsa until they're deported, many workers expect to be laid off on Oct. 31, accelerating the return to Mexico.

Laying low in Tulsa: While Tulsans with U.S. citizen and permanent resident status will most likely stay put, those without legal documents have three options. The first is staying in Tulsa and adopting a wait-and-see attitude.

Antonio Barrera, 24, worked in construction in Tulsa for $13 an hour, helping to build St. Francis Heart Hospital. He returned home in early October.

''Most of them are going to chance it and stay in Tulsa to save their houses and trucks,'' Barrera said.

''They're more discreet,'' Becerra said. ''It's not like it used to be: drinking, shouting and gunshots. People are saying, 'I'll drink at home from now on.'

''The streets are deserted now. On Fridays, Mexicans just load up the car with groceries and go home.''

Moving east: The second option for illegal immigrants in Tulsa is to move on to another state with more lenient immigration laws.

Arkansas is the most frequently mentioned destination.

''It's safer there, and there's lots of work,'' said Becerra, who said that if he were to go back to the United States, he'd go to Arkansas.

''Lots of people are planning on moving there,'' he said.

Chicago, Dallas and Denver were other destinations mentioned, as many immigrants have family members in those cities.

Going home: Gustavo Bernal, 60, the mayor of Casa Blanca and a retired elementary-school teacher, described the return to Casa Blanca as ''a forced, panicked retreat.''

He said about 500 more people are expected to come home, putting an enormous strain on local services.

Tulsa residents are sending home whatever they own, mostly furniture and major appliances.

About 20 such trips have already made it to Casa Blanca, Bernal said.

Filled to the brim, these pickups and trailers are driven by people who hold visas. Casa Blancans in Tulsan who own two trucks are sending one home now and keeping the other for the return home.

Dr. Soriano has seen the signs of this phenomenon. Many people have come to her for medicine because they're going back north, not to immigrate, but to bring more truckloads of belongings back, she said.

Maria Elena Gaytan, 37, is a shopkeeper in Casa Blanca. Her brothers have been in Tulsa for seven years, and they're among the ones returning.

''People are coming back who lived in Tulsa for seven to 10 years,'' Gaytan said. ''They had kids, houses and belongings up there.

''They're coming back home with whatever they can salvage.''

Esparza said many of those returning are young families who had left for Tulsa in the last six years.

''They're sending home the kids, the ones that were raised in Tulsa. The American Dream fizzled out for them. They hadn't planned on coming back, but they were just so afraid.''

Reversing the trend: Cristian Becerra Bernal, 15, is a high school student in nearby Zacatecas. He's one of the potential migrants thinking twice about heading to Oklahoma.

''I wanted to go to Tulsa, but I don't want to anymore,'' he said. ''If I go, I'll get caught. I might go to a different place in the U.S. This has been all over the TV, and nobody wants to go north now.''

Mayor Bernal said: ''About 50 families a month are coming back. The tide has turned. Before, nobody was coming home.''

The pipeline from Casa Blanca to Tulsa began in 1950s

The link between Casa Blanca, Mexico, and Tulsa dates back to the 1950s, when three brothers made their way to Oklahoma through Texas.

The Becerra brothers, natives of the tiny north-central Mexico town, were picking cotton in Texas through government-sponsored programs. When the cotton harvest was over, they didn’t go back to Casa Blanca. They came to Oklahoma.

The brothers found jobs in Tulsa as maintenance painters at an apartment complex. Then, as the stories go, they started recruiting other people from their hometown, telling them to come to Tulsa, where there were jobs and friendly people from home. Thus an invisible pipeline of illegal immigration was established between the two cities.

Fermín Quiroz Becerra, 65, is the last of the three brothers. He returned to Casa Blanca years ago, but thousands of his friends, relatives and their friends and relatives remain in Tulsa.

Casa Blanca, Mexico

Location: North-central Mexico, about 22 miles east of Zacatecas, capital of the state of Zacatecas.

Population (2000 census): 1,092 residents.

Demographics: 74 men for every 100 women over age 18; Thirty-two percent of households are headed by women.

Average educational attainment: Fourth grade. Income: Only 10 workers make more than $200 a month.

Work: 57 percent of the working population have agricultural jobs.

The Tulsa connection: More than 3,000 people from the Casa Blanca area live and work in Tulsa, mainly in construction, house painting and gardening.