After months of asking, agents from the FBI questioned the only known suspect in the Sept. 11 attack on the U.S. consulate in Benghazi that killed four diplomats, the suspect’s Tunisian lawyer told The Associated Press Saturday.

Ali Harzi, a Tunisian, was detained in Turkey and extradited to Tunisia in October where authorities have said he is “strongly suspected” of being involved in the attack.

His lawyer, Anwar Oued-Ali, added that Harzi was also questioned about an attack on the U.S. embassy in Tunisia, a few days later, suggesting the American authorities are looking into if there is a connection between the two attacks.

The Sept. 11 assault by armed men in the Libyan city of Benghazi killed U.S. Ambassador Chris Stephens and three other American diplomats. Members of an Islamist militia, Ansar al-Sharia are suspected in the strike, but there has been little progress in the Libya-based investigation into the attack.