Will the police station check all chat records?

Yes.

But under normal circumstances, the user's chat history information will not be queried.

Of course, the user's information records will be queried only in extremely large cases.

Not only the chat records of various instant messaging APPs, but also the files, address books, text messages, call records, notepads, calendars, etc. on the mobile phone. Even if they are deleted, they can be recovered.