Neurensic has built a solution, SCORE, for doing Trade Surveillance using H2O (an open-source pure Java Big Data ML tool), Machine Learning, and a whole lot of domain expertise and data munging. SCORE pulls in private and public market data and in a few minutes will search it for all sorts of bad behavior: spoofing, wash-trading and cross-trading, pinging, and a lot more. It then filters down the billions of rows of data down to human scale with some great visualizations - well enough to use as hard legal evidence. Indeed SCORE and it's underlying tech is not just used by companies to police themselves; it is being used by the public sector to find and prosecute the Bad Guys. I'll close with a demo of a Real Life bad guy - he was defrauding the markets out of 10's of millions - who got caught via an early alpha version of SCORE. All data anonymized of course, so you'll have to go hunt last years Wall Street Journal to find his name for real.