Minority investors in Oxbow Carbon, fresh off a major Delaware Court of Chancery victory, are now investigating up to $50 million in payments Oxbow made to founder and CEO William Koch’s attorneys at Mintz, Levin, Cohn, Ferris, Glovsky and Popeo.

Robert J. Hurst and Barry Volpert, principles in Crestview-Oxbow Acquisition, said in a books-and-records complaint Wednesday that they were targeting ”corporate waste and inappropriate spending” on Mintz Levin, which had served Koch’s interests despite signing on to represent Oxbow in a two-year suit over Crestview’s right to force Oxbow’s sale.