A former Citigroup Inc. trader claims the bank purposely mischaracterized his comments in online chat groups to try to make him its scapegoat in a U.S. criminal probe of foreign-exchange price fixing.

Rohan Ramchandani alleges in a suit seeking $112 million in damages that a former Citi executive reviewed thousands of his chat communications, many containing trader jargon, and misleadingly "translated" them for prosecutors in a way that falsely implicated him. He was found not guilty after a trial in 2018.