Complex sentence: Adolfo Calero Portocarrero was a leader of the Contras and opponent of the Sandinistas, he was charged with controlling the bank accounts into which money was deposited and then used to buy supplies and arms.
Split into simpler sentences: Adolfo Calero Portocarrero was a leader of the Contras and anopponent of the Sandinista government. He was responsible for managing the bank accounts into which money was deposited and then used to buy supplies and arms.