Updated

A former Marine staff sergeant has been sentenced to 12 years in prison after he pleaded guilty to receiving child pornography while stationed in Afghanistan.

At his federal court hearing Monday in Portland, Ore., Corey McAdoo of Vancouver, Wash., said he took full responsibility for his actions.

Judge Robert Jones called the case a "real life tragedy," saying McAdoo was a "poster guy for the Marines" until he engaged in conduct the judge described as "unforgivable."

Portland police received a tip that a Portland woman had sent videos of herself sexually abusing her infant nephew to McAdoo. The U.S. attorney's office says a joint state and federal investigation showed the woman also sexually abused two other juvenile nephews at McAdoo's request. The Marines removed McAdoo from active duty and turned him over to the FBI to face federal charges in Oregon. He was later separated from the Marine Corps.

Inez Lambert previously pleaded guilty to sex abuse charges and is serving a 25-year state sentence.