Given a paragraph about movies, and a set of conversational question answers about the paragraph, answer a follow-up question from the paragraph. The paragraph has the prefix 'CONTEXT:'. Each conversation question has a prefix `Q:` followed by the answer prefix `A:`, and the follow-up question has a prefix `FOLLOWUP_Q:`.
Q: CONTEXT: It is not explained, but we can theorize. We don't know when he rented those books. He might have done so before buying his own (to ensure he indeed should buy them), or because the books weren't easy (or cheap) to purchase. Also remember that instead of renting books on a subject he is well versed in, he probably became well versed on the subject thanks to renting those books. Finally, despite those books in his apartment, IIRC we are never told what those books are about. They might have had nothing to do with the seven deadly sins (John Doe wanted to avoid having incriminating evidence on his home, perhaps?), and thus all of his knowledge came from renting the books in the library. The books in his house might have been educational on a ton of other subjects or philosophies. Also keep in mind, the Internet still wasn't a thing back then. And books such as the ones mentioned (on bondage, homicide, or by Italian Dominican friars) might have not been easily found in your regular old book store. Finally, you can also claim that he rented them to make the plot move along, as this was their main lead.  <sep>  Q: Why did John Doe need to check out books at a public library? A: It is not explained, but we can theorize  <sep> FOLLOWUP_Q: What is your theory?
A: 
Internet still wasn't a thing back then