Secretary of State Hillary Rodham Clinton said Tuesday that a team of FBI agents has arrived in Libya to investigate the deaths of four Americans who were killed when the U.S. Consulate in Benghazi was overrun last week.

The FBI’s arrival had been delayed by concerns about continued violence in the eastern Libyan city. Clinton did not provide any details of how many agents were involved or whether the team has arrived in Benghazi yet.

“The FBI has joined the investigation on the ground in Libya and we will not rest until the people who orchestrated this attack are found and punished,” Clinton told reporters after a meeting with Mexican Foreign Minister Patricia Espinosa at the State Department.

U.S. Ambassador J. Christopher Stevens and three other State Department employees were killed when a protest linked to an anti-Muslim video turned violent and an armed mob stormed the consulate and set it ablaze.

Libyan officials said that as many as 50 people have been brought in for questioning in connection with the attack. Most of them are regarded as witnesses who were outside the consulate at the time of the protest, the officials said.

Clinton defended the security in place before the attack, repeating the administration’s position that the combination of Libyan guards and U.S. personnel was sufficient. She also said there had been no intelligence or other warnings of an impending attack on the consulate.

In Cairo, Egypt’s general prosecutor issued arrest warrants Tuesday for seven Egyptian Coptic Christians and a Florida-based American pastor, referring them to trial on charges linked to the video.

A Libyan woman places a flower at the gate of the U.S. Consulate in Benghazi, Libya, on Monday. (Mohammad Hannon/AP)

The case is largely symbolic, because the seven men and one woman are believed to be outside Egypt. Among those charged is Nakoula Basseley Nakoula, an Egyptian Copt living in Southern California and believed to be behind the video. Also among those charged are Florida-based pastor Terry Jones, who has said he was contacted by the filmmaker to promote the video, as well as Morris Sadek, a conservative Coptic Christian in the United States who pushed the video on his Web site.