Logan Melgar hadn't had a drink on June 4.

The Green Beret sergeant's dry day became a key to unraveling the narrative spun by the elite Navy commandos whom military investigators now suspect killed him, officials familiar with the case said.

Melgar, a staff sergeant in the Army's 3rd Special Forces Group, was specifically selected for an intelligence operation in the West African nation of Mali. He was well respected by the American Embassy staff and the partner forces there, a former U.S. Africa Command official said. But shortly before he died, Melgar told his wife that he had a bad feeling about two of his partners in that effort, both of whom were members of SEAL Team Six.

Not wanting to say much more, Melgar informed his wife, Michelle, that he'd tell her the full story when he got back home, according to an official speaking on condition of anonymity because the investigation is still ongoing.