Conversation so far:
What made Peter Sutcliffe investigation difficult?
It was one of the largest investigations by a British police force and predated the use of computers. Information on suspects was stored on handwritten index cards.
What else made Peter Sutcliffe investigation difficult aside from being a large investigation predating the use of computers?
Aside from difficulties in storing and accessing the paperwork, it was difficult for officers to overcome the information overload of such a large manual system.
What did the difficulties in storing?
The floor of the incident room was reinforced to cope with the weight of the paper.

Question: Why did the officers struggle?
Self-contained rewrite: Why did the officers struggle during the Peter Sutcliffe investigation?