Federal authorities have filed the first criminal charges in the investigation of the deadly terror attack on the U.S. diplomatic compound in Benghazi , Libya , people briefed on the matter said . Several suspects charged in the armed assault last September 11 include prominent Libyan militia figure Ahmed Abu Khattala , the sources said . Other identities were not disclosed . The counts initially sought months ago in New York are still under seal , according to the sources . The investigation of the attack that killed Ambassador Christopher Stevens and three other Americans continues , these people said , as investigators try to build their case against Khattala and others who authorities believe were involved . If CNN can interview Benghazi suspect , why ca n't FBI ? Justice Department spokesman Brian Fallon declined to comment as did FBI spokesman J. Peter Donald in New York . But word of the development comes as the Justice Department has come in for sharp criticism from congressional lawmakers about the pace and progress of the investigation . Attorney General Eric Holder had earlier this year promised them that the Justice Department would soon make public what actions it would take . Republicans have demanded more aggressive steps from the incoming FBI Director James Comey . But people close to the case said the investigation has moved significantly in recent months . In that time , the FBI has released photos of what it called persons of interest who were present during the attacks , seeking tips from the Libyan public . It could n't be learned when the United States plans to announce the charges or whether there is any intention to try to detain Khattala or the others . None of those briefed on the matter would discuss the precise counts . Benghazi attack timeline . In a recent interview with CNN 's Arwa Damon , Khattala acknowledged being at the Benghazi mission after the attack but denied any involvement . Benghazi has become a political flashpoint in a long-running battle between the Obama administration and Republicans , who accuse it of not bolstering security before the attack , of botching the response to it and of misleading the public for political gain less than two months before the November election . The investigation is led by agents from the FBI in New York and has included some members of the Washington field office , who have traveled to Libya to interview hundreds of witnesses , those briefed on the investigation said . Khattala told CNN that he had not been questioned by either Libyan authorities or the FBI . U.S. law enforcement officials said it 's not unusual for the FBI not to seek to interview defendants in a case while they collect other evidence . The Benghazi attack involved scores of militants using rocket-propelled grenades and other weapons . Stevens took refuge behind a fortified door with heavy metal bars to keep the attackers from breaking in . But they set fire to the mission -- a villa -- with diesel fuel . Stevens was overcome by smoke . U.S. Rep. Adam Schiff , a Democratic member of the House Intelligence Committee , said in an interview on `` The Lead with Jake Tapper '' that he would not describe the investigation as proceeding rapidly . `` It 's been frustrating for many of us that it has n't moved faster , but it is a very difficult working environment for our agents , '' said Schiff . `` Gathering evidence in Libya , you might imagine , is very difficult , finding , interviewing witnesses , extremely difficult . '' But Schiff said there has been progress . `` We have identified many of the parties involved . We 're still trying to identify what the command-and-control structure would be . A lot of missing pieces still , but we are finally making progress , '' said Schiff . King : Why Benghazi matters .
FIRST ON CNN : Charges filed against Libyan militia leader Ahmed Abu Khattala , others . Attack last September killed Ambassador Christopher Stevens and three other Americans . TL;DR The U.S. government has charged a Libya-based group with planning the deadly attack on an American diplomatic compound in Benghazi, Libya. The Benghazi attack has become a political flashpoint in Washington .