BENGHAZI, Libya (AFP) - An improvised bomb exploded outside the headquarters of the public prosecutor in the Libyan city of Benghazi causing material damage but no fatalities, a security source said Monday. “Initial evidence suggests the device was a suitcase packed with high yield explosives (TNT),” an investigator at the scene told AFP, adding that there were no casualties. The overnight blast marked the third attack on the site in 2012, he said.