Ines Perez and her husband were unable to have children.

Then a Jesuit priest introduced them to Dr. Eduardo Vela, an obstetrician in Madrid who said he knew a woman who had become pregnant during an affair and did not want to keep the baby. But this would not be a standard adoption.

The doctor told Perez to use a pillow to fake pregnancy. Then when he finally handed her the baby, he signed a birth certificate saying that she and her husband were the biological parents.

“Look, what a gift!” he said that day in June 1969. “I have a girl for you.”

The couple named the baby Ines, like her new mother. Her surname came from her new father, Pablo Madrigal.

That’s the story Ines Perez had always told her daughter.

Now, nearly 50 years later, it will be revisited in court. Vela, now 85, is scheduled to go on trial Tuesday in Spain on charges that he stole Ines Madrigal — one of tens of thousands of babies taken from their biological parents during the long dictatorship of Francisco Franco. Vela is the first person to face trial in the decades-long saga.

“For us victims, this case is very important because it could set jurisprudence for other courts around Spain,” Madrigal said in an interview. “Everyone knows that this country has been a baby supermarket for 50 years and nothing has been done about it.”

The story of the country’s “lost children” began to come into public view in 2008 as part of a broad investigation by a crusading judge, Baltasar Garzon, into human rights violations under Franco, who came to power at the end of the Spanish Civil War in 1939. Garzon estimated that in the first 15 years of the fascist dictatorship, more than 30,000 children were taken from their leftist parents in an official campaign by the government to minimize the societal impact of “Marxist genes.”

The children were given to families deemed more deserving. Their names were changed and they were issued identification documents that affirmed their new family lives and erased their pasts.

Amid allegations that Garzon had abused his office by opening the Franco-era files, Spain’s National Court halted his investigation before anyone could be charged.

By then, it had become clear that the practice of baby stealing continued well into the 1960s — though the motive had morphed from political ideology to business opportunity — and to a lesser extent even after the dictatorship ended in 1975.

Nuns and priests were often complicit in the thefts. Some mothers were told that their babies had died during childbirth.

Antonio Barroso, who founded the National Assn. for Victims of Irregular Adoptions after discovering he had been bought from a priest in the city of Zaragoza, estimated that as many as 300,000 babies may have been stolen between 1965 and 1990. He was told that the parents who raised him paid 150,000 pesetas in 1969, roughly the price of a new car at the time.

Madrigal reached out to Barroso in 2010 after reading a news article about the baby thefts. When she sent him her documents, he told her they had been falsified.

Both she and her mother — by then a widow — had come to have serious doubts about her origins.

In 2012, Madrigal persuaded her mother to testify before a judge, even though it meant potentially incriminating herself as party to an illegal adoption. Her testimony helped lead to the charges a judge brought against Vela in April 2016.

Vela is charged with abduction, illegal adoption and document fraud, as well as faking a birth or altering the identity of a child.

No evidence has been presented that he profited in placing Madrigal.

During the judicial investigation, Vela argued that the false information on Madrigal’s birth documentation was the result of a clerical error. He said that he signed papers without reading them as he was too busy.

Both Vela and his lawyer declined to comment.

The doctor founded the San Ramon Clinic in Madrid in 1962. Many of his patients came from reformatories that Franco had established for “fallen women” who had gotten pregnant out of wedlock. Vela worked as a visiting doctor at several reformatories and referred women to his clinic when they were due.

Under the lax adoption laws of the time, it was possible for doctors to indicate “unknown mother” on the birth certificate as if the baby had been abandoned — with little official scrutiny. In a country where abortion remained illegal until 1985, many young women who had gotten pregnant by accident may have been happy to remain anonymous.

In 1981, a magazine reported on strange goings-on at San Ramon, where women claimed they had been told their babies had died under suspicious circumstances. Some said they had been shown a corpse — a claim supported by a photographer who sneaked into the clinic and took a picture of a dead baby in a refrigerator. Vela later said that he had been performing an autopsy on the corpse.

The police opened an investigation, but nothing came of it. Vela left the clinic in 1982, and it closed two years later. In 2010, he was caught on camera telling undercover journalists who said they were looking for their biological parents that he had destroyed the files from San Ramon because they were “super dangerous for me.”

He continued to practice as a gynecologist and obstetrician in Madrid — catering to trendy mothers choosing old-school home birthing — until he was accused in the stolen baby scandal in 2013.

Though the upcoming trial is focused solely on the theft of Madrigal, her lawyer, Guillermo Pena, alleged that Vela was a key player in a national network.

Pena said it is unclear how many babies Vela may have helped steal.

“Children were sent outside Madrid and even abroad,” he said. “If San Ramon had eight birthing rooms operating over a 20-year period, the number could be enormous. If Vela was not the mastermind, he was one of the main operators.”

When the trial begins, hundreds of activists are expected to gather outside the courtroom. Many are searching for their biological parents.

“We don’t want revenge or [to] see him go to jail,” said Mari Cruz Rodrigo, the president of the Madrid branch of SOS Stolen Babies. “We want this man to speak and tell us what he knows, the truth. He is one of the big fish, but a lot of people have been involved in this, in Madrid and all over Spain.”

Another person allegedly involved was Maria Gomez Valbuena, a nun who was accused of being a fixer for the stolen baby network. She was charged with kidnapping and falsifying documents but died in 2013 at age 87 before she could be tried.

Madrigal is now a 49-year-old train station clerk and life coach with 10-year-old twin sons.

As much as she is looking forward to the trial, she said it will also take a toll on her.

“It’s going to be very damaging emotionally because it will stir things up inside of me,” she said.

She has given up hope that Vela will reveal the identity of her biological mother.

“I’ve come to the conclusion that this case is something that goes beyond me and my life, and it is all for the cause,” she said. “That’s why I’ll be there.”

Ines Perez will not be at the trial. She died at age 93 in 2016 — eight months after charges were filed against Vela.