They say he fought tirelessly for the Libyan people and didn't think twice about putting his own life at risk.
This is a sad day for the vast majority of Libyans. Ambassador Stevens was instrumental in helping rebel forces defeat four decades of dictatorship.
He just returned to Libya four months ago, to help that nation build a democracy.
Stevens was admired by many, including Mouath Baesho, a CU Denver student from Libya who knew and worked with Stevens.
"He is a hero to most of the Libyan people," Baesho said.
Stevens was the leader of an outpost in one of the most dangerous places on earth.
"He risked his life staying there in Libya," Baesho said. "It's sad news. For a guy that I met face to face, he really cared about the relationship between the two countries."
Stevens was among four Americans killed in a fierce and focused attack on the 11th anniversary of 9/11.
Demonstrators were protesting a YouTube video that mocks the prophet Muhammad. A similar rally in Cairo, Egypt was not deadly.
U.S. officials suspect Islamic radicals planned the attack at the U.S. embassy in Benghazi, Libya.
Nader Hashemi is the director of the Center for Middle East Studies at DU. He says Stevens was a fearless advocate for the Libyan people during the uprising that took down their late leader Muammar Ghadafi.
"He died in the city he helped liberate," Hashemi said. "There will be, I can guarantee you, streets, boulevards named after Ambassador Stevens precisely because of the important role he played."
Hashemi calls Libya an Arab Spring "success story," in spite of this latest violence.
"So it's important that we not lose sight of the bigger picture," he said. "The bigger picture is the transition to democracy in Libya."
He says it's important not to let extremist groups set the agenda.
"He really cared about the Libyan people," Hashemi said.
Baesho says Stevens would have wanted the struggle for democracy to continue.
Stevens was only 52 years old. He's the first U.S. ambassador killed in the line of duty in 33 years.
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