Complex sentence: They learn through an ex-priest who worked trying to rehabilitate pedophile priests that there should be approximately 90 abusive priests in Boston and, through their research, develop a list of 87 names and begin finding the victims to back up their suspicions.
Split into simpler sentences: They learn through an ex-priest who worked trying to rehabilitate pedophile priests that there should be approximately ninety abusive priests in Boston. Through their research, they develop a list of eighty-seven names, and begin to find their victims to back up their suspicions.