In 1994 a 13-year-old boy named Nicholas Barclay from San Antonio Texas disappeared without a trace, but the real mystery began when he came back.

Nicholas was last seen playing basketball with his friends at a park near his home. His mother, Beverly Dollarhide, says he called her to pick him up, but Nicholas's older brother Jason answered the phone and told the boy to walk home instead. That was the last time anyone spoke to Nicholas.

The boy was known as a "troubled child," and in the past he had run away from home, so his parents weren't surprised when he went "missing" for a few days. After all, Nicholas only had $5 in his pocket the night he disappeared, so where could he go?

But after searching for days, police found no sign of Nicholas. Jason claimed to see the boy sneaking around near their garage a few months later, but after that there were no sightings. Three years later, after giving up hope of finding Nicholas, the Dollarhide family received a surprising call.

Nicholas had been found in Spain, where he claimed to have been kidnapped and abused in a child sex ring. Nicholas's older sister Carey visited him in Spain and confirmed his identity, and soon he was back home in Texas.

Nicholas's family celebrated his return, and local news stations covered his miraculous recovery, but one detail about the young man convinced a San Antonio private investigator that he wasn't really Nicholas.

It turned out he was right.

Find out who the impostor was, and what happened to him, on the next page!

From the beginning, anyone who paid close attention could spot a number of things wrong with "Nicholas" and his story.

He claimed to have amnesia, so he couldn't remember details about his childhood, and explained that he spoke with a French accent because of his time overseas, but there were other details that revealed the truth.

Nicholas had blue eyes, but the impostor's were brown. His hair was also darker. But what the keen-eyed investigator noticed about Nicholas was his ears: they had changed over the years, which is impossible.

After fingerprinting the impostor he was finally identified as Frédéric Bourdin, a 23-year-old French man who had stolen Nicholas's identity after seeing a news report about him. Bourdin had lived as an identity thief and con man in Europe, and tried to start a new life as Nicholas in America.

Bourdin was convicted of passport fraud and perjury, and served 6 years in an American prison before moving back to France and posing as another missing teenager, then he did the same thing again in Spain after being released. Over the years, Bourdin claims to have impersonated more than 500 people.

As for the mystery of what really happened to Nicholas Barclay, Bourdin has a shocking theory about the truth, and it explains why Nicholas's family played along with his lie.

Read what Bourdin has to say about the case on the next page!

While Nicholas's mother Beverly and his sister Carey seemed to believe Bourdin's story, his older brother Jason never did.

"When he came to see me, he didn't look at me like Nicholas," Bourdin said in a documentary about the case. "He didn't pretend to look at me like Nicholas. And he said 'Good luck' to me, and he left."

Investigators question why the family would let a stranger into their home when he was obviously not who he claimed to be, and Bourdin believes he was part of the family's cover-up.

"They knew I was not Nicholas," Bourdin said, "They didn't believe a word that I said. But they were good at not showing it." Whenever Bourdin didn't know something he should have known, Carey or Beverly would answer for him.

"They killed him," he insists. "Some of them did it, some of them knew about it, and some of them choose to ignore it. I wasn't worried about Nicholas coming back no more."

Jason, who was one of the prime suspects for the murder, died of a drug overdose years later, meaning the mystery of Nicholas Barclay's disappearance may never be solved.

Of course, Bourdin is also a big liar, so maybe we shouldn't just take his word for it. In 2007 the con man married and started a family, and since then he's pledged not to impersonate anyone else.

What really happened to Nicholas? Share this unbelievable true story and tell us what you think!