Almost everything about the continuing hostage crisis at the Ain Amenas natural-gas complex in Algeria appears as obscured as the Sahara in a sandstorm, but one thing came into focus Friday as American Frederick Buttaccio, of Katy, Texas, was confirmed dead by the U.S. State Department.

Buttaccio's cause of death was not provided in the statement made by State Department representative Victoria Nuland and reported by the Associated Press.

"We express our deepest condolences to his family and friends," AP quoted Nuland as saying. "Out of respect for the family's privacy, we have no further comment."

However, reported it had confirmed Buttaccio died of a heart attack during a raid by the Algerian military, which targeted the al Qaeda-linked terrorists who began taking hostages Wednesday.

U.S. officials told AP that Buttaccio's remains were recovered Friday. They spoke on condition of anonymity because they weren't authorized to speak publicly on the matter.

Several members of Buttaccio’s family declined to comment when contacted at their homes, the Houston Chronicle reported. Buttaccio was 58, the Chronicle said. Katy is a Houston suburb.

At this point, it is unclear what kind of work Buttaccio was doing at the natural-gas plant at the time of his death.