Some experts said that the Libyan government, which has integrated some of the rebel militias into its security forces, has been reluctant to tackle the growing lawlessness. The consulate attack, however, could bring pressure on Tripoli from the United States and other countries to get tough, they said.

“I think, of course, there is going to be some anger, some soul searching,” said Salman Shaikh, director of the Brookings Institution’s Doha Center. “But it should make the Americans that much more determined to push the Libyans to take on the serious issues in the country: the security apparatus and the establishment of a proper state.”

Benghazi is home to perhaps the widest array of armed groups, some of which help protect the city.

Some Libyan officials suggested that remnants of the Gadhafi regime were responsible for the attack. Deputy Interior Minister Wanis al-Sharif told a press conference on Tuesday that the United States should have protected its personnel better in the wake of threats and the film that mocks the Prophet Muhammed, which Muslims consider blasphemous.

"They are to blame simply for not withdrawing their personnel from the premises, despite the fact that there was a similar incident when al-Libi was killed. It was necessary that they take precautions. It was their fault that they did not take the necessary precautions," Sharif said.

Stevens’ death marked the loss of one of the State Department’s best Libyan experts.

A former Peace Corps volunteer in Morocco, Stevens focused most of his diplomatic career on the Middle East, spending time in Cairo, Riyadh and Jerusalem. He first served in Libya in 2007 and returned in the spring of 2011 in the early days of the uprising.

At the time, he met with officials who would become key members of the National Transitional Council and eventually Libya’s first democratically elected government, which was seated last month. He became ambassador in May.

An Arabic speaker, Stevens told McClatchy during a spring 2011 interview that he particularly loved Libya, even as he served as a diplomat there during Gadhafi’s time. Other diplomats remembered him as deeply engaged in all the Middle East, however.

"He knew our issues really well," said Abi Khair, a diplomat at the Jordanian embassy in Washington who had met Stevens in the days after Gadhafi’s fall when Khair served with the United Nations. "He was passionate about them."

Stevens moved easily in Libya. He ordered local food, sat with ordinary Libyans and with his unassuming nature, slowly cajoled rival factions to rebuild their country.

Stevens’ cables on Libya, which were among the trove released by WikiLeaks, offered colorful insights on Gadhafi and al Qaida’s push to expand in Libya.

In an August 2008 cable he wrote to prepare then Secretary of State Condoleezza Rice for a visit with Gadhafi, he described the Libyan leader as “a self-styled intellectual and philosopher, he has been eagerly anticipating for several years the opportunity to share with you his views on global affairs.” During the fall of his regime, Libyans recovered a photo album Gadhafi had made containing photos of Rice.

When asked by McClatchy about the blunt nature of his cables, Stevens simply smiled and shrugged.

Youssef reported from Cairo, Ali Zway reported from Benghazi and Landay reported from Washington. Hannah Allam and Matthew Schofield contributed from Washington. Also contributing were McClatchy special correspondents Jon R. Stephenson in Kabul, Afghanistan, Alan Boswell in Nairobi, Kenya, and Adam Baron in Sanaa, Yemen.