When cops subpoena your Facebook info, here's what FB sends.
It is actually a 2 part process. First we call FB and tell them to "freeze" the account, in which they take a screenshot in time of the site so if anything is deleted, then it isn't lost. Then the warrant gets signed and the info goes over to FB. They then hand over historical data.
We do this for threats in schools and various other violent offendeer situations.