You need proofs first to sue someone, and that whats the banks needs for them to give the personal informations of the owner of the bank. There are lots of things to do and crypto scam investigations are way harder than normal money laundering scams and frauds. If the banks are being played, then it could mean that any information you wish to acquire from them are certainly not possible.
And banks won't be helping it anyway. They don't easily do it and it needs a lot of verification and process towards the claim and besides they wouldn't disclose it just because someone said that they got scammed by that account holder and will just end up not recovering the money.
The least we can do now yet wise is not to invest in icos and just spend our money in most established coins.