Wassana stands in front of a rented room in Bangkok,Thailand.

BANGKOK — When the young Thai woman saw an online ad seeking surrogate mothers, it seemed like a life-altering deal: $10,000 to help a foreign couple that wanted a child but couldn’t conceive.

Wassana, a lifetime resident of the slums, viewed it as a nine-month solution to her family’s debt. She didn’t ask many questions.

In reality, there was no couple. There was instead a young man from Japan named Mitsutoki Shigeta, whom she met twice but who never spoke a word to her. This same man — reportedly the son of a Japanese billionaire — would go on to make surrogate babies with 10 other women in Thailand, police say, spending more than half a million dollars to father at least 16 children for reasons still unclear.

Mitsutoki Shigeta father of 16 babies

The mystery surrounding Shigeta has riveted Thailand and become the focal point of a growing scandal over commercial surrogacy. The industry that catered to foreigners has thrived on semi-secrecy, deception and legal loopholes, and Thailand’s military government is vowing to shut it down.

Wassana’s story, which she shared with The Associated Press on condition that her last name not be used to protect her family and 8-year-old son from embarrassment, offers clues into an extraordinarily complex puzzle that boils down to two questions: Who is Shigeta and why did he want so many babies?

Shigeta is being investigated for human trafficking and child exploitation, but Thai police say they haven’t found evidence of either. The 24-year-old, now the focus of an Asia-wide investigation, has said through a lawyer that he simply wanted a big family.

He has not been charged with any crime and is trying to get his children back — 12 are currently in Thailand being cared for by social services. His whereabouts are unknown; he left Bangkok after police raided his condominium Aug. 5 and discovered nine babies living with nine nannies. Police say he sent DNA samples from Japan that prove he is the babies’ father.

Key to unraveling all of this are the women Shigeta paid to bear his children. And Wassana, whose account has been corroborated by police, was his first.

Shigeta Mitsutoki with baby at Bangkok Airport

AN ANSWER TO EVICTION

Wassana’s Bangkok is not the city of skyscrapers and spas that most visitors see. The petite, soft-spoken 32-year-old with a ninth grade education has spent her life in a trash-strewn slum, scraping by selling traditional Thai sweets from a food cart and sharing a mildew-stained tenement with seven relatives. At $6 a day, it was affordable until her late father’s medical bills drained the family’s savings. They couldn’t pay rent for a year and faced eviction.

So when her sister stumbled upon an ad seeking surrogates in 2012, Wassana didn’t hesitate.

“I thought that any parents who would spend so much money to get a baby must want him desperately,” she says. “The agent told me it was for a foreign couple.”

She assumed it was customary to keep the biological parents’ identities confidential. In a country where deference to authority is expected — especially for poor, uneducated women — she didn’t probe.

She wondered, though, who the baby’s mother was.

“I don’t know if the doctor used my eggs or another woman’s,” she says. “Nobody told me.”

During the pregnancy, she developed pre-eclampsia, a condition that causes dangerously high blood pressure. She was rushed into the delivery room two months early and on June 20, 2013, she underwent a cesarean section, giving birth to a boy. Wassana’s family came to visit, but, she says, Shigeta did not.

The infant was placed in an incubator and after six days, Wassana returned home. She’s not sure when the baby was released from the hospital to Shigeta’s custody.

Two months later, she finally met Shigeta for the first time at the New Life fertility clinic, which had posted the Internet ad.

He was tall, with shaggy, shoulder-length hair, and was dressed casually in jeans and a wrinkled, button-down shirt he left un-tucked. His lawyer had accompanied him to the meeting, where he and Wassana signed a document granting him sole custody.

He wasn’t personable. There was no “thank you” for carrying his child, she says. There was, in fact, no communication at all.

“He didn’t say anything to me,” she says. “He never introduced himself. He only smiled and nodded. His lawyer did the talking.”

PERJURY ALLEGATIONS

A month later, the same lawyer, Ratpratan Tulatorn, called and told her to go to the Juvenile and Family Court to finalize the custody transfer. Under Thai law, a woman who gives birth is the legal mother, and, if she is married, her husband is the legal father. A court approval is required to transfer custody, which experts say often involves perjury.

In 1999 Japan’s youngest self-made billionaire, Yasumitsu Shigeta

Police Col. Decha Promsuwan, who has questioned five of Shigeta’s surrogates, said several of the women told police Ratpratan had instructed them to tell the court they’d had an affair with Shigeta, resulting in a child their husbands did not want.

Ratpratan said he is no longer Shigeta’s attorney and declined to comment on the women’s statements, saying, “I don’t want to touch that point because it’s a legal matter.”

During the hearing, Shigeta told the judge he owned a finance company in Japan.

His story is being intensely followed in Japan despite legal threats against the press. After his case made headlines, a group of prominent lawyers sent letters warning Japan’s mainstream media not to report Shigeta’s name or the names of his family members, according to news organizations that received the letter.

However, several Japanese magazines and online publications have identified him as a son of Japanese tycoon Yasumitsu Shigeta, founder of mobile phone distributor Hikari Tsushin.

Yet even his heritage is shrouded in mystery. The company says it can neither confirm nor deny the father-son relationship, calling it “a personal matter,” and Thai police and Interpol say they are investigating his family ties. Multiple stock filings, meanwhile, show the elder Shigeta has a son named Mitsutoki and his company has a shareholder with the same name. The stock papers show that Yasumitsu’s child was born Feb 9, 1990, the same birthdate as the Mitsutoki Shigeta at the center of the surrogacy scandal, according to Thai media that published his passport page.

Yasumitsu Shigeta did not respond to a request for an interview and Mitsutoki Shigeta’s current lawyer did not respond to requests for interviews with his client, who has multiple addresses throughout Asia. Phone calls to a Hong Kong mobile number listed for the younger Shigeta went straight to voicemail, and he did not answer text messages. No one answered the bell at his Hong Kong condo, and the doorman said he could not recall ever seeing him there.

’10 TO 15 BABIES A YEAR’

In early August, barely a year after Wassana’s court date with Shigeta, she saw his face again — this time, on television. She almost didn’t recognize him; his hair was now neatly trimmed.

The Thai media was calling it the “serial surrogacy” case. It had broken just after another scandal involving an Australian couple who paid a Thai surrogate to carry twins, then left behind the one with Down syndrome.

Wassana was floored. What was happening?

Police wondered the same thing. So intricate was Shigeta’s quest for children that they crafted a flowchart to keep track of how he did it.

The 9-step diagram starts with Shigeta’s picture and traces the steps he took to get his babies, from hiring surrogacy clinics and nannies, to registering apartments in the infants’ names and completing legal paperwork required for birth certificates and passports. The deliveries were spread out at nine Bangkok hospitals.

Shigeta’s acquaintances offer varying accounts of his motives.

The New Life clinic, which is currently closed pending investigation, stopped working with Shigeta after two surrogates got pregnant and he requested more, said founder Mariam Kukunashvili.

Shigeta told New Life “he wanted to win elections and could use his big family for voting,” Kukunashvili said. “He said he wanted 10 to 15 babies a year, and that he wanted to continue the baby-making process until he’s dead.”

Kukunashvili said she reported his requests to Interpol in an April 8, 2013 fax to its French headquarters, but never heard back. Thailand’s Interpol office said it never saw the warning.

She rejected Wassana’s account that the New Life agent had portrayed the parents as a couple and withheld Shigeta’s identity.

“At New Life, surrogates are always informed fully and never treated this way,” she said.

The Medical Council of Thailand, meanwhile, spoke with Wassana’s doctor, Pisit Tantiwattanakul, before he closed his All IVF fertility clinic and emptied it of all patient files after the scandal broke. His whereabouts are unknown, but he has vowed to present himself for a police interview in early September.

Pisit told the council Shigeta said he had businesses overseas and wanted a large family because he only trusted his own children to take care of them.

Interpol has asked its regional offices in Japan, Thailand, Cambodia, Hong Kong and India to probe Shigeta’s background. Police say he appears to have businesses or apartments in those countries.

Japan has no law banning surrogacy, but the medical industry has issued orders against it that are strictly followed, which could explain why Shigeta flew to one of the few places in Asia where it is openly practiced. Since 2010, he has made 41 trips to Thailand and police say he traveled regularly to Cambodia, where he holds a passport and brought four of the babies. Cambodian police have refused to comment on the case.

One of the babies in Cambodia might be Wassana’s — a prospect that leaves her riddled with guilt.

“What if they’ve done something bad to the baby?” she says. “Did I deliver him to some terrible fate?”

Today, her own fate is uncertain. The money she received for bearing Shigeta’s child cleared the family debt but was not enough to drag them out of the slums. She still lives in the same derelict tenement.

She has held the boy just once, when Shigeta handed him to her briefly in court. But she told police that she would be willing to raise him if he is being mistreated.

“I thought he would be with a good family that would love him,” she says. “That’s what I thought.”