After Sunday’s 60 minutes expose on high-frequency traders “rigging the stock market”, the Global Markets president of BATS William O’Brien, went on CNBC to challenge his accusers directly and rudely.

After O’Brien accused author Michael Lewis and Brad Katsuyama of lying in order to promote a business Katsuyama said “You want to do this? Let’s do this.” What followed was Katsuyama laying out how BATS allows high-frequency traders to “scalp” other market participants by using fast computers to front run trades.

The front running process was also articulated in the 60 Minutes segment:

Michael Lewis: The insiders are able to move faster than you. They’re able to see your order and play it against other orders in ways that you don’t understand. They’re able to front run your order.

Steve Kroft: What do you mean front run?

Michael Lewis: Means they’re able to identify your desire to, to buy shares in Microsoft and buy ‘em in front of you and sell ‘em back to you at a higher price. It all happens in infinitesimally small periods of time. There’s speed advantage that the faster traders have is milliseconds, some of it is fractions of milliseconds. But it”s enough for them to identify what you’re gonna do and do it before you do it at your expense.

Katsuyama claimed BATS allowing people to be ripped off defeated the purpose of an exchange which is supposed to be built for the buyers and sellers to come together not for the middle men who stand between them. Allowing high-frequency traders to scalp people adds unnecessary costs to buyers and sellers who need to raise money for their businesses.

O’Brien then changed tactics and accused author Michael Lewis of lying about contacting BATS for his book “Flash Boys.” Lewis said he did in fact visit BATS and that there was little point in talking to O’Brien who was “throwing dust in the air.” Lewis also noted that David Cummings, not O’Brien, was in charge of BATS at the time he was writing the book in February of 2013.

O’Brien came off as defensive and at times desperate but whether or not regulators will look into high-frequency trading is an open question. New York Attorney General Eric Schneridman has now said he believes some high-frequency trading practices “may be illegal.”