David Christie, Chairman of Bleckwen, joins Marie and Sam to chat about the amazing world of behaviour detection and how Bleckwen has harnessed machine learning to better detect fraudulent and suspicious behaviour. With a name linked to a "truth serum", Bleckwen has been involved in some "deep truth" investigations dealing with better detection of complex fraud such as PPP fraud, where it is a challenge for banks with larger legacy systems. Credit origination fraud, synthetic ID fraud, and oddities in transaction monitoring patterns, according to David it's all about behaviour.  Marie dives into the use of graph theory - did you know it was used to design London's tube system? - the same approach is used by Bleckwen to identify patterns across banks accounts and parties, how they interact, how often and other similarities.  David also explains how they encourage their team to go further afield to keep their thinking fresh - could Tweets prior to the Catalan unrest in 2018 have helped to detect it earlier?  Sharing their intelligence and some of their algorithms to the wider financial crime prevention community (for free) is an important part of Bleckwen's approach to being a part of the financial crime community.