Complex sentence: Brigadier Imtiaz Ahmed alias Billa (b.? -) is a former director of Pakistan's Intelligence Bureau (IB) between 1990-1993 and former senior operative in the Inter-Services Intelligence (ISI).
Split into simpler sentences: Brigadier Imtiaz Ahmed alias Billa (b.? -) is a vetern intelligence officer. He is former director of Pakistan's Intelligence Bureau (IB) between 1990-1993 and former senior operative in the Inter-Services Intelligence (ISI).