KNOXVILLE, Tenn. — The Pilot Flying J diesel rebate fraud scheme cheated not just trucking companies across the U.S. but the federal government, according to the man who says he helped crack the case. John Verble, a former broker at Morgan Stanley Smith Barney's Knoxville branch office, says he was fired in 2013 for working with the FBI as an informant in the Pilot case and for alerting authorities to other questionable dealings he says he stumbled upon during his work there. The brokerage ...