Complex sentence: On that occasion, two men who arrived in the car were challenged by the Ambassador's bodyguard, and said they had come for visas, but when asked to produce their passports, they left hurriedly.
Split into simpler sentences: On that occasion, two men who arrived in the car were challenged by the Ambassador's bodyguard. They said they had come for visas, but when asked to produce their passports, they left hurriedly.