(CBS/AP) TRIPOLI, Libya – The Libyan doctor who treated U.S. ambassador Christopher Stevens says the diplomat died of severe asphyxiation and that he tried for 90 minutes to revive him.

Ziad Abu Zeid told The Associated Press on Wednesday that Stevens was brought to the Benghazi Medical Center by Libyans the night before, 동해출장샵 with no other Americans and that initially no one realized he was the ambassador.

More in U.S. compound attack in Benghazi

Abu Zeid said Stevens had “severe asphyxia,” apparently from smoke inhalation, causing stomach bleeding, but had no other injuries.

Assault on U.S. consulate in Benghazi leaves 4 dead, including U.S. ambassador

Stevens, U.S. Foreign Service officer Sean Smith and two other Americans died when a mob attacked the consulate in the port city of Benghazi. The crowd fired guns and rocket-propelled grenades and set fire to the consulate.