NEW : U.S. Rep. Nancy Pelosi is in Libya to lead a congressional investigation . Al - Hassan was arrested at an airport in Tripoli on Friday , Libyan authorities said . He was the security chief for Libya 's President Gadhafi . He is wanted by the International Criminal Court .
NEW : U.S. Rep. Nancy Pelosi is in Libya to lead a congressional delegation . Al-Senussi was arrested at an airport in Mauritania on Friday , Libyan authorities said . He was the intelligence chief for Libya 's Moammar Gadhafi . He is wanted by the International Criminal Court .