The UBS banker known as "Pete the Greek" won't be prosecuted for his connections to those who had roles fixing the Libor interest rate. (Libor is the London interbank offered rate, which governs the interest banks pay each other for loans.) The Financial Times reports that the FCA's regulatory decisions committee decided it had not proven its case against Panagiotis Koutsogiannis, despite an internal company chat message that appears to indicate he knew what was going on. Koutsogiannis got his nickname because his colleagues could not pronounce his real name. Koutsogiannis' messages to his colleagues came out in the trial of Tom Hayes, the UBS and Citi banker who was sentenced to up to 14 years in prison for his role in fixing the rate. Here's an example of one of Koutsogiannis' messages, according to the FT: In a chat from April 2008, Mr Koutsogiannis requested “low fixing pls.” Then in June 2009, he wrote to another colleague: “JUST BE CAREFUL DUDE.” The colleague responded: “i agree we shouldn’t be talking about putting fixings for our positions in public chat.” Hayes communicated directly with Koutsogiannis by email, according to Bloomberg: “Hi mate, we have a big 1m fixing position over the next month,” Hayes wrote in a July 1, 2008, e-mail shown to the jury by prosecutors Friday. “My question is can I use some balance sheet in the market for 1m? We really need to get the fixing down.” The move would “save the bank about 1m USD,” he added.Join the conversation about this story » NOW WATCH: The 'Uber of helicopters' can get you from Manhattan to JFK for much less than you think