Transcript for Family: Detained US man in Russia was visiting for wedding

Overseas now, where a 48-year-old American and former marine is in custody in Russia, accused of being a spy. His family says he's innocent, and that he was there to attend a wedding, and now the state department is involved. ABC's James Longman with the E the tails coming in. Reporter: Tonight, the family of Paul Whelan, a former marine, speaking out. The only goal, the only idea we have is to get him back. Reporter: His brother says he was in Russia last week for a wedding and had toured Moscow with friends the Friday he vanished. We realized that something had gone wrong and Paul wasn't where he was supposed to be, but no one knew where he was. Reporter: On Sunday, friends filed a missing person's report. Then Russian security services put out this statement yesterday, saying they have "Initiated a criminal case against a U.S. Citizen under article 276 of the criminal code of the Russian Federation." Article 276? Espionage. Tonight, he's being held by authorities in Russia, but his brother firmly denies the allegations. There's no chance that Paul was engaged in espionage in Russia. Reporter: The 48-year-old heads up security for a michigan-based auto parts company, but has a checkered past in the U.S. Armed forces. After two tours in Iraq, he was discharged for hasny. A self-professed russophile, Whelan was active on Russian social media. Spy scandals have long been part of the theater of u.s./russia relations. This arrest comes just two weeks after the guilty plea of confessed Russian agent MARIA butina, who admitted to infiltrating Republican political circles to influence u.s./russian relations. No word yet from the state department whether or not they've spoken to Whelan. The charges against him are serious, and if convicted, he could face a minimum of ten years in prison. Tom? James Longman for us tonight.

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