Transcript for Family pleads for release of American under arrest in Moscow

We turn to the mystery surrounding an American man arrested in Moscow on charges of spying. Paul Whelan, a former marine, attending a wedding in Moscow taken into custody. His family speaking out and our chief global affairs correspondent Martha Raddatz has more. Reporter: Paul Whelan was the director of global security for a Michigan auto parts company but this was a personal trip. The marriage of a fellow former marine to a Russian woman. This morning, a family is pleading for the release of Paul Whelan, the former American marine placed under arrest in Moscow after accusations of espionage. His twin brother insisting it's all a big mistake. There's no chance that Paul was engaged in espionage in Russia. Reporter: He had traveled to Russia several times before and posted frequently on Russian social media. His brother insisting Whelan was in Russia only for the wedding and his friends filing a missing persons report as he fell silent two days earlier, something that is out of character for him. We had realized something had gone wrong and Paul wasn't where he was supposed to be but no one knew where he was. Reporter: It follows on the heels of MARIA butina's guilty plea. Russian president Vladimir Putin has disputed butina's background but two weeks ago she admitted to infiltrating conservative U.S. Political circles to influence u.s./russian relations which are already tense amid multiple rounds of U.S. Sanctions against Russian officials and private companies. We've made clear to the rulgss our expectation that we will learn more about the charges come to understand what it is he's been accused of and if the detention is not appropriate, we will demand his immediate return. Reporter: Whelan is supposed to be allowed a consular visit in the coming hours where they hope to gain more information, George. Whelan served two tours in Iraq but was discharged for bad conduct. Reporter: Exactly. While his family talks about his service in the Marine Corps he was discharged in 2008 for bad conduct related to larceny and reduced in rank after two tours in Iraq, George. Martha Raddatz, thanks very much.

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