A man believed to be connected to the attack on a U.S. consulate in Benghazi has been detained by Libyan authorities, CNN reported Thursday.

The suspect, Faraj al-Shibli, was detained shortly after returning from a trip to Pakistan. It is unclear what involvement he had in the attack, which left U.S. Ambassador Christopher Stevens and three other Americans dead.

Al-Shibli is currently the only suspect in custody. Another suspect, Ali Hamzi, was briefly detained and interrogated by the FBI in Tunisia. He was released by a Tunisian judge in January.