JPMorgan Chase & Co. has placed on leave two of its metals traders, Gregg Smith and Michael Nowak, as a U.S. criminal investigation into the bank's metals trading practices is underway, a source for Reuters says. JPMorgan, which deals a lot in gold trading globally, is being probed over metals spoofing trades. Nowak and another former JPMorgan trader, Robert Gottlieb, are defendants in at least one other civil suit related to metals spoofing at the bank. Christiaan Trunz and John Edmonds, former JPMorgan metals traders, have already pleaded guilty to spoofing charges, the news outlet noted.