U.S. investigators visit Libya compound where ambassador was killed But, until now, the agents apparently have remained in Tripoli. In Washington, U.S. Attorney General Eric Holder suggested the probe had been active despite the weeks-long delay in getting FBI agents to Benghazi. You should not assume that all that we could do or have been doing is restricted solely to Benghazi. There are a variety of other places, in-country and outside the country, where relevant things could be done and have been done," Holder said at a press conference. "This is a matter that's been under active investigation almost since the time of the incident, and I'm satisfied with the progress that we have made," he said. Separately, the Pentagon on Thursday confirmed the visit of an FBI investigation team to Benghazi, and said U.S. military personnel provided support to the mission. But a spokesman indicated the FBI team had since departed. "At the request of the FBI, the department provided logistic and security support to the investigation team in order to conduct work on-site in Benghazi," Pentagon spokesman George Little told reporters. (Department of Defense) personnel completed that support earlier today and have departed Benghazi along with the investigation team. In Benghazi, the road leading to the compound's front gate was blocked by vehicles mounted with weapons belonging to the Libyan security forces, a Reuters witness said. Reporting by Omar al-Mosmary and Ali Shuaib in Tripoli Additional Reporting by David Ingram and Phil Stewart in Washington; Writing by Marie-Louise Gumuchian; Editing by Andrew Osborn and Vicki Allen