I have had occasion to contact Facebook in the past for an underage client who's Facebook page was hacked and personal pictures were replaced with some extreme pornography.
I found them extremely helpful - they rang me almost immediately after I emailed them about the hack and defacement. They froze the account and pages and all access logs as soon as I supplied a Garda Pulse Incident reference number and retained the data in the event that the Garda CCIU required them to proceed with investigation.
They do however have very strict privacy rules in relation to access to personal pages and will never grant access to someone elses pages without a court order.