Harvey Kesner, a former partner at New York-based securities litigation firm Sichenzia Ross Ference, is suing Baker Botts and one of its partners for $35 million, accusing the Am Law 100 firm of extortion for its threats to sue on behalf of his former client, who is separately suing Kesner for alleged conflicts and fraud.

Kesner’s suit, filed Tuesday in federal court in New York, alleges “racketeering, tortious interference with contract and business expectancies, intentional infliction of emotional distress, prima facie tort, and misconduct” by Baker Botts and partner Jonathan Shapiro.