A former Skadden, Arps, Slate, Meagher & Flom associate has sued Sullivan & Cromwell in New York state court for $13 million, accusing the firm of double-dealing in an international arbitration matter in which a partner served as chair of the panel.

Andrew Delaney, a New York attorney who has represented clients in Southeast Asia since 1993, represented a Thai company that developed a coal-fired power plant in Laos that was expropriated by the country’s government. According to the complaint, after an arbitration panel chaired by a Sullivan partner awarded his client $56 million, the firm then represented the government of Laos to fight the award.