I personally think that the police should have everyone's data readily available whenever needed since it will help keep our society safe and stable. Even though one may not be suspected of any crime, their personal information may contain pieces of evidence about others. For example, if a man is suspected of a crime, the police should be able to access personal information of his family, friends, relatives, colleagues... (like call logs to him, any money transfer from or to this man in bank statements, any contacts and so on). However, the police should make it clear to all the people whose data is being used that their data is being used for additional investigation.