Complex sentence: Police appealed for information about her disappearance, and issued a photofit of the lorry driver who had given her a lift, but despite the publicity he was not identified, and by 25 December investigators were working on the theory that he may have abducted her.
Split into simpler sentences: Police appealed for information about her disappearance, and issued a photofit of the lorry driver, but he was not identified. By 25 December investigators were working on the theory that he had abducted her.