Ambassador Stevens believed strongly that an attack was likely, and made multiple unambiguous requests for additional security in Libya.
In June 2012, the Consulate in Benghazi, Libya was damaged by an improvised explosive device. Stevens reported to his superiors that an Islamist group (Ansar al-Shariah?) had claimed credit for the attack. Shortly after that a British Embassy convoy in Benghazi was also attacked. And again, Ambassador Stevens requested more security forces for Benghazi.
Karen Keshap and Shawn P. Crowley, State Department employees, as well as Eric Nordstrom the State Department's Regional Security Officer, all made multiple complaints about the inadequate security in Benghazi. Crowley, had even apologized in an email for "being a broken record" on the subject of inadequate security in Benghazi.
In response to all these requests, the Obama Administration refused to increase security at the US Consulate in Benghazi, at all.
On the morning of September 11, Ambassador Stevens signed a three-page cable, labeled "sensitive," in which he noted "growing problems with security" in Benghazi. As before, he was ignored.
On the evening of September 11, in what would become his last known public meeting, Stevens met with the Turkish Consul General Ali Sait Akin, and escorted him out of the consulate front gate at about 8:35 PM. It is a little surprising that such a high-level meeting - between a full Ambassador and a Consul General - would occur at a relatively small Diplomatic Mission. Such a meeting would have to have been sanctioned, or even ordered, from the highest levels of our government.