Transcript for 8-year-old in Brazil at the center of an international tug-of-war

We're going to turn next tonight to the alleged kidnapping case making international headlines now. The American father, fighting to get back his 8-year-old son. His inlaws arrested as they flew into the U.S. Here's kayna Whitworth. Reporter: This 8-year-old at the center of an international tug of war. His father battling his ex-wife and family for almost five years to bring him home to Texas. No doubt that they illegally abducted my child. There's no doubt they have retained him and there's no doubt they've done everything in their power to prevent me from having my son in my life. Reporter: In 2013, his ex-wife took their son with his permission to Brazil for a family wedding. They never returned. Just yesterday, federal agents arresting his grandparents at Miami international airport as they attempted to enter the U.S. The affidavit alleging they conspired to kidnap Nico to their native Brazil. Just the glimmer of having him back here at home is why I've been fighting for five years. Reporter: A judge in Brazil granting Marcelle sole custody, but an FBI investigator said the judge never gave Brann an opportunity to appear in court. It comes after an another international abduction made headlines. David Goldman fought five years to bring his son home to new Jersey. In 2009, a Brazilian court finally awarded his father custody. And Brann says he's leaned on Goldman for advice. Nico's grandparents are set to appear in court on Monday.

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