The Judge, Marine Maj. Nicholas Martz, delivered his verdict on Monday in the bench trial of Cpl. Wassef Hassoun.
Hassoun was also convicted of causing the loss of his service pistol. He was found not guilty of a theft charge related to his gun.
Prosecutors had argued the Marine had prepared to flee to Lebanon after threatening to leave his base in Fallujah in 2004. But defense attorneys claimed he was kidnapped by insurgents.
According to US Marines Spokesperson Capt. Stewart Coles, Hassoun faces up to 7 ½ years in prison, reduction in rank and a dishonorable discharge.
Sentencing is expected later this week.
