Their child, Nicholas Barclay, had been missing from Texas for 3.5 years. Out of the blue, the family got a call from Spain saying he had reappeared.
They world-renowned child psychiatrist knew beyond a shadow of a doubt the man couldn’t be from America 
because at 13 years old, his Texan accent would be cemented. Speech is developed primarily until age 7-8. Even three years of being forced to speak French wouldn’t erase the initial dialect patterns formulated in early childhood.
The second big tip-off was the ears. Ears maintain their shape throughout the lifespan. And this imposter had Darwin’s tubercles. The Texas missing boy didn’t. The ears were diffierently shaped, so everyone knew the two could not be the same.
Come to find out the imposter, Bourdin, had stolen youth identities over 500 times in 15 different countries. In France, they called him, “le chamillion.”
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Interesting science behind the “why not” when it would be so easy to believe. I can’t believe, but really am not surprised, that someone would impersonate a long lost relative. Such a tragedy for the people living the experience.
That would be one of the most terrible things for a grieving family that thought they were reunited with a missing loved one. And he had apparently done this numerous times. The Texas family in the documentary, had apparently tricked the trickster though. Authorities suspect the TX people had killed their missing son, and that’s why they let this imposter stay for so long without “recognizing” a dark-haired, brown-eyed Frenchmen wasn’t their blonde haired, blue-eyed son.