The FBI on Thursday released the photographs of three men it said were at the U.S. diplomatic mission in Benghazi, Libya, when it was attacked last September.
The FBI did not call the three men suspects in the attacks, saying only that they "may be able to provide information to help in the investigation."
"The FBI is now asking Libyans and people around the world for additional information related to the attacks," the U.S. investigative agency said in a statement with the photographs.
Four Americans including U.S. Ambassador to Libya Christopher Stevens died in the attacks on September 11, 2012, on a poorly guarded temporary U.S. diplomatic mission compound and a more fortified CIA compound nearby.
No individuals are known to have been charged in the attacks.