Last week, the U.S. Ambassador to Libya and three other Americans were killed in an attack in Benghazi, Libya.  Even after Ambassador Chris Stevens' body has been returned to the United States, we're still just learning details of what happened.  Today, we begin a week of special reports on his death, part of our ongoing series on national security.

FOX News Radio's Courtney Kealy, who reported extensively from Libya during the uprising has Part one of our series, "Death of an Ambassador":

Securing America.

Chris Stevens worked with the Libyan rebels before Muammar Qaddafi was overthrown.

(President Obama) "It's especially tragic that Chris Stevens died in Benghazi because it is a city that he helped to save."

President Obama capped Stevens' State Department career, naming him U.S. Ambassador to Libya, based in Tripoli.  In an email this summer, Stevens told friends, "People smile more and are much more open with foreigners.  Let's hope it lasts!"

But Stevens and three other Americans were killed this September 11th on an ill-fated trip to Benghazi.  What remains unclear is how Stevens and his team of security experts - who had access to classified intelligence and threat levels - became trapped in a bombardment they may have not seen coming.

Courtney Kealy, FOX News Radio.

Click HERE to read Courtney Kealy's American Dispatch on Ambassador Stevens' death