Given the task definition and input, reply with output. In this task, you're given a story (which contains five sentences only). Your task is to find all the characters which are available in the given story.

Sentence1: Ed's dad was abusive. Sentence2: He often beat Ed with a belt. Sentence3: One day in gym class, his teacher saw the belt marks. Sentence4: He pulled Ed aside and asked him some questions. Sentence5: Then he sent the police to arrest Ed's dad!
Ed, Police, Teacher, Dad