(CBS News) Christopher Stevens is the first United States ambassador killed in the line of duty since 1979.
The night of his death, CBS News has learned, Stevens spoke with a business developer building a trauma center in Benghazi, Ethan Chorin. Chorin, one of the last people to speak with Stevens, described an ominous phone call he had with Stevens about an hour before he died.
"I had been speaking with him, about 9:00, about arrangements for him to come to Benghazi Medical Center the next morning and he had referred me to his security detail, whether it was the regional security officer or another one of their detail. Something was happening, and he told me very curtly that, understandably, he was very concerned, he hung up the phone," Chorin recounted.
There are always risks for Americans serving overseas, but Stevens believed the mission was worth it.
When Libyan rebels were looking for a friend in their fight against Muammar Qaddafi - they didn't have to look far to find Christopher Stevens. He had seen the brutality of the Qaddafi regime first hand while serving in the U.S. Embassy in Tripoli.
Instead of watching the country fight its bloody revolution, Stevens boarded a cargo ship and returned to help.
President Barack Obama said of Stevens, "With characteristic skill, courage and resolve, he built partnerships with Libyan revolutionaries, and helped them as they planned to build a new Libya."
He was as much an architect as a cheerleader. When he was quickly confirmed as ambassador, he couldn't contain his excitement.
He made a video introducing himself to the Libyan people, but most in Benghazi already knew who he was. He said in that video, "I'm excited to return to Libya to continue the great work that we've started."
But in that same jubilant city that had welcomed him before, came his end just four months later. Secretary of State Hillary Clinton said Wednesday, "He risked his life to stop a tyrant, then gave his life trying to build a better Libya."
Stevens grew up in Northern California, but the foreign world always beckoned. After law school it was the Peace Corps, and then the Diplomatic Corps, serving in places like Cairo, Riyadh, and Jerusalem.
His cultural wisdom was well respected back in Washington, both as an idealist and a realist.
Arizona Sen. John McCain said of Stevens, "(He) was not unaware the danger that he faced. He was privy to intelligence information and others. But he went forward to did his job with a smile, with love of his country and love of the country where he was serving."
His family knew the risks, too. Steven McDonald, a close college friend, said, "I just remember his mom saying, 'Well, why are you going over there anyway?' and he said, 'Well, mother, to help the Libyan people and to represent the United States interests in this country.' It's such a waste."
Diplomats by their very nature are unsung, serving far from home in sometimes remote and hostile outposts.
The average American rarely knows their names. But we know one now and a nation mourns.
Watch Lee Cowan's full report in the video above.