On his deathbed five years ago in Barcelona, Juan Moreno told his son Juan Luis the family secret: we bought you from a priest in 1969. Moreno Sr. paid 150,000 pesetas, more than what he paid for their apartment seven years earlier. DNA tests have revealed that Juan Luis’s birth certificate, which names his adoptive parents as his birth parents, is false. And Antonio Barroso, Juan Luis’s best friend, was also bought from the same priest, according to Juan Luis. The two families would take summer vacations together to Zaragoza, around 300 kilometers west of Barcelona, but the men now believe the trips’ true purpose was to pay the installments on the two boys to the clergyman, Juan Luis says.

“My adoptive family gave me plenty of love, but it’s also true that my life has been a lie,” Juan Luis says over the telephone from Barcelona.

Moreno is one of thousands of Spaniards who suspect that doctors, nurses, priests, and nuns stole and sold babies between the 1960s and the early 1980s. While the 1,500 open cases vary, a common story has a woman being told her newborn has died shortly after birth. The baby is sold to another couple, and official papers are doctored so this couple appeared as the biological parents. At one infamous Madrid clinic, now closed, called San Ramón, it was reported in the Spanish media that staff kept a dead newborn in the freezer to prove to mothers that their babies had died.

Spanish police investigated a handful of cases in the early 1980s, but only within the last few years has the nationwide scope of the alleged trafficking started to take shape.

On Thursday, a Madrid judge is scheduled to question 80-year-old Sister María Gómez Valbuena on charges of illegal imprisonment (it is called illegal imprisonment instead of kidnapping because under Spanish law kidnapping involves a ransom). The case began when Marisa Torres filed accusations against the nun after meeting her daughter Pilar, now 29, for the first time last year. Torres had gone to Sister María at the Santa Cristina clinic in 1982 after seeing a magazine ad for expectant mothers who needed social assistance. Torres had separated from her husband, and the father of the baby was another man.

Torres told a judge last week that after giving birth, Sister María intimidated her into giving up the child. The nun, Torres said, threatened to denounce her to authorities for being an adulteress, saying they would likely take away her 2-year-old daughter. When Pilar and her adoptive father began to investigate her roots, they spoke to Sister María. She told them Pilar’s mother was a prostitute and to forget about her, Pilar said. Sister María hasn’t responded to the charges.

Despite the recent number of cases being investigated, Spanish authorities have largely avoided the issue in the past, taking years to confirm what people had been talking about for decades (Sister María, for example, was named in a story in Interviú magazine about alleged child trafficking at her clinic in 1982). To assist those searching, Moreno and Barroso decided to found Anadir, now the largest association, of around 1,100 people, who are looking for parents, children, and siblings.

“It’s sad that the Spanish justice system is incapable of doing its job,” Moreno says. “We’ve given them false birth certificates, false death certificates, we’ve opened empty coffins, and supplied hundreds of testimonies. What more do they need?” This Thursday, the Spanish justice minister will be meeting with representatives of some of the families to discuss their grievances.

Internet groups have connected searchers across the country. Websites and Facebook pages abound with stories and pleas:

“I’m looking for my biological family. I was adopted in 1961 and my papers are full of irregularities. Thanks and good luck to everyone.”

“I’m searching for my brother or sister, born in Bilbao on January 27, 1972. They took the baby away right after the birth. Strange things happened, and a few hours later they told my mother that the baby had died. They refused to show it to her.”

“I’m looking for my brother who was born on October 11, 1964 in Málaga and was said to have died four days later, but it doesn’t appear that he was buried. We know that the dates and places of birth are not reliable.”Courts are now looking into baby-trafficking cases in Valencia, the Basque Country, Madrid, Catalonia, Andalusia, and the Canary Islands.

“I view this baby-stealing network like a mafia,” says Enrique Vila, a Valencia-based lawyer who works on behalf of the five associations that provide support for people looking for their biological families. “If this wasn’t organized, how did babies born in Valencia end up in Galicia, around 1,000 kilometers away?” The Catholic Church in Spain has declined to respond to the allegations, and declined to talk to The Daily Beast for this story.

Vila, who was adopted and suspects he might have been taken from his biological mother, said that he believes hospital staff perpetrated these thefts for money and the church acted as a distribution network. “The nuns and priests justified what they did by saying that the child was better off with the adoptive family, but they still took the money,” he said.

Even legal adoptions signed by a judge and sealed by a notary have been found to contain false information, as revealed in numerous investigations brought by adopted children and their families. So there is a heightened sense of uncertainty among Spanish adoptees. Last year in Barcelona, during the first meeting between a mother and her 40-year-old daughter, the latter read her own death certificate.

With nothing to trust, Spaniards are erring on the side of suspicion. But sometimes the trails don’t lead to trafficking. Last year a woman from León, Spain, whose twin sister supposedly died at birth, began to question the official story after reading about other cases in the press. On the Internet she found a woman who shared the same age and an uncanny resemblance. DNA tests, however, came back negative. Likewise, a few recent grave exhumations and subsequent DNA tests showed no wrongdoing. Nevertheless, other exhumations have revealed coffins filled with rocks, an adult femur, and the bones of another baby, according to various reports in the Spanish media.

Allegations of church-condoned baby trafficking are not confined to Spain. Investigations by the press and the government into similar allegations in Australia found that Catholic hospitals from the 1950s to 1970s coerced women using drugs to sign adoption papers or to simply knock them out long enough to whisk the baby away. Catholic Health Australia, the largest nongovernment health provider in the country, has formally apologized for what happened.

The effects of the Spanish trafficking have reached the United States as well. Austin-based Randy Ryder thought he was born in the Spanish city of Málaga to his Austrian mother and American father, but the truth came out 12 years ago. Last October, Ryder appeared in a BBC report because a Spanish woman believed him to be her lost brother. DNA tests proved negative, but his biological mother, who now lives in London, saw the show and reached out to him on Facebook. This time, the DNA matched.

New Yorker Maria Washbourn was born in Spain in 1961, but through the church and an intermediary was adopted by an American couple. A friend noticed a physical resemblance between her and a Madrid man, Vicente González Olaya, who writes a blog about the search for his missing older sister. “It’s a long-shot,” says González, who also covers the auto industry for El País newspaper, “but we’re waiting for the DNA results to come back.”

González has kept an online record of his investigation, an often surreal account of dealing with the church, hospitals, DNA labs, and Spain’s vast bureaucracy of registrars and archives.

The nuns, he said, told his devoutly Catholic mother that the baby had choked to death on the umbilical cord, even though his mother saw the child alive. After his parents died early last year, González started to make some inquiries. Nothing made sense.

“We have a family plot, but she’s not there,” González said. “So I checked all the other cemeteries in Madrid and she’s not there either. Nor is there any document that I have seen that says my mother lost a child. The more I find, the more I’m convinced that she is alive.”