Well for starters I qualified that it can be quite easy, which isn’t to say that I’m deciding who is and isn’t guilty of financial crime. Neither is Monzo bank making that decision.
We’re looking for indicators of things that suggest a financial crime is occurring on an account. We are often provided with some of those indicators, along with intelligence, from external agencies. There a whole manner of things that we use when making our decisions that, prior to working in financial crime, I just hadn’t thought about being something that were even obvious in the banking system, let alone investigated.
If we think enough of those indicators exist then, as all financial institutions are obliged to, we submit a SAR to the NCA. It’s then up to them to act and push it through the court system, they decide whose guilty not us. We don’t inform other banks that we’ve closed a customers account, but the NCA might do so.
We are judge and jury, but we are obliged to operate within the law - whether or not you agree with that law is a different argument.