(CNN) -- U.S. forces working with the FBI captured a key suspect in the 2012 attack on the American diplomatic compound in Benghazi, Libya, a U.S. official told CNN Tuesday.
Libyan militia leader Ahmed abu Khattalah was captured over the weekend, the official said. His is the first arrest in connection with the attack.
He is now being held in a location outside Libya, the official said.
Last year, federal prosecutors filed sealed charges against Khattalah over the Benghazi attack, in which scores of militants using rocket-propelled grenades and other weapons attacked the compound.
U.S. Ambassador Christopher Stevens and three other U.S. citizens died in the attack, which later became a political flashpoint.