Ask further details from your bank and particularly ask for the transactions which are market into lien (charge back) and crisis check with the receipts of your LocalBitcoins to find which transaction and buyer claimed the charge back.
Nowhere on this planet will the police investigating fraud tell you what is wrong with your account and what transactions are involved before the end of the investigation.
For example, here banks are actually forced to not give out any information, anyone telling their clients any bit of information that was requested by the police also faces charges.
So only option is to wait for a call from them or for next update from bank.
Exactly! Contacting the bank and trying to get details about why this happened might be a waste of time when they unblock your account (if!) you will be notified, contacting the police will also be probably a waste of time as they will not give you any details nor they will need any statement from you as they would have asked you already.
Unfortunately, at this point, you're basically out of options. Hope you don't have all your money stuck with that bank account.