Wassef Ali Hassoun, now 31, went missing twice from the military first in June 2004 in the purported kidnapping at the hands of Islamic extremists, and again in January 2005, when he failed to return to Camp Lejeune, N.C., after a visit to Utah to see relatives.
He was charged twice with desertion, and his whereabouts remain unknown, although Sands said Sami Hassoun told him on the phone that his brother was in Lebanon.
Last month, however, Sami Hassoun contacted Sands and asked if a book and movie deal the family had tried to negotiate in 2005 then refused to sign might be revived.
"They come back, reappear six years later as if they had amnesia," said Sands, a contractor who has worked with the Pentagon and various branches of the military. "This is a very compelling story, but there is a dark shadow over [Wassef] and he needs to come clean."
Sands said clearing the name of Wassef Ali Hassoun would require him to take responsibility for his actions by returning to the U.S. to face military sanctions.
But Sami Hassoun backed away when pressed to answer questions about what happened to his brother in 2004, including what proof exists of the kidnapping and whether Wassef was abused by his captors, Sands said.
In one e-mail, Sami Hassoun said he has the answers but then asked Sands to "send the numbers to us so we can move forward," a reference to the book and movie deal.
Soon after, Sami Hassoun claimed he was pursuing other offers involving the project, according to the e-mails. He did not respond to multiple e-mails from the AP seeking comment.
Wassef Ali Hassoun was an Arabic translator who joined the Marines following the September 2001 terrorist attacks. His strange saga began June 20, 2004, when he failed to report for duty at Camp Fallujah in Iraq.