The information from old newspapers tell us about the feelings and actions of common people of the country. This information may be affected by the personal views of the news editor, but from these, the historians can infer what common men thought about the incident.
On the other hand, the information in police reports tells us only about what officials thought, what they were interested in and what they wished to preserve for future generation. These records do not always help the historians understand what other people in the country felt and what lay behind their actions.