Complex sentence: Assigned to investigate the murder, Apollo discovers Fisk was heavily involved in the black market, and that Vice President Gaius Baltar and Colonel Saul Tigh were among Fisk's trading partners.
Split into simpler sentences: Assigned to investigate the murder, Apollo discovers Fisk was heavily involved in the black market. He also discovers that Vice President Gaius Baltar and Colonel Saul Tigh were among Fisk's trading partners.